Biological and ecological features of the stellate weaver sawfly. Red-headed sawfly, or social star sawfly weaver

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1 Federal Forestry Agency All-Russian Scientific Research Institute of Forestry and Forestry Mechanization STAR SAW TKACH: HARMFUL, FOREST PATHOLOGICAL SURVEYS IN THE SOCKS AND PROTECTION MEASURES Pushkino 2015

2 UDC LBC 44.9 Z 43 Reviewers: Yu. A. Sergeeva, Ph.D. biol. sci., head. laboratory of biological methods of forest protection VNIILM EA Sadomov, Ph.D. s.-x. Sciences, Secretary General of the VPRS MOBB. Star sawfly-weaver: harmfulness, forest pathological examinations in foci and protection measures / Yu. I. Gninenko, G. A. Sery, E. Yu. Bondarenko. Pushkino: VNIILM, p. Color insert Acantholyda posticalis Mats. is one of the most important pests of young pine forests of natural and artificial origin in a number of regions of Russia. To protect against damage caused to pine crowns by its larvae, biological preparations have not been developed. It is important to be able to correctly conduct all types of forest pathological examinations in the centers of mass reproduction of this phytophage, to analyze the pronymphs and eonymphs collected during the examination. The methods of analysis of weaver specimens and the timing of the main work in its centers are given. The brochure is intended for workers in the protection of forests, forestry, as well as students of specialized higher and secondary specialized educational institutions. Reviewers: U.A. Sergeeva, PhD, manager of biological forest protection laboratory, VNIILM. E.A.Sadomov, PhD, secretary general of VPRS MOBB. Pine web spinning sawfly its hazard, forest pathology surveys in its mass outbreaks and protection operations. U.I. Gninenko, G.A. Sery, E.U. Bondarenko, Pushkino: VNIILM, b. Pine web spinning sawfly Acantholyda posticalis Mats. Is one of the most hazardous pests in young natural and man-made pine forests in a number of Russian regions. There are no biological preparations to protect pine crowns against damage by its larvae. It is important to conduct correct forest pathology surveys of all types in this phytophage mass outbreaks, to analyze collected pronymphs and zoonymphs.pine web spinning sawfly species analysis procedures and key operations periods in its mass outbreaks is provided. The paper is designed for forest protection specialists as well as students of high and secondary specialized institutions. The work was reviewed and recommended for publication at a meeting of the methodological commission, protocol 2 from ISBN VNIILM, 2015

3 Contents Introduction... 4 Weaver sawflies of the genus Acantholyda... 6 Brief information about biology and morphology... 9 Outbreaks of mass reproduction of the star sawfly weaver in the USSR and Russia Measures to localize and eliminate foci of the star weaver sawfly Forest pathological examinations Laboratory analyzes of the state of the populations of the star sawfly-weaver on individuals collected during a detailed survey Sanitary cuttings in pine forests affected by damage by the star sawfly-weaver Organization and implementation of forest pathological supervision over the dynamics of the number, forecast of the occurrence of centers of mass reproduction Conclusion List of references Appendix 1 JOURNAL of the results of the operational survey Annex 2 CARD for recording the number of star sawfly weaver in the soil weaver-weaver Appendix 5 STATEMENT for calculating the threat of crown eating in the foci of the star sawfly weaver

4 INTRODUCTION Star weaver sawfly Acantholyda posticalis Mats. (Hymenoptera, Pamphiilidae) is one of the widespread pests of pine stands in Russia. The centers of its mass reproduction often cover large areas of young pine stands in a number of regions of the European part of Russia, the Southern Trans-Urals, in the south of Western Siberia, in the Altai Territory and Transbaikalia. In recent years, foci of the weaver sawfly have also begun to form in the Tver and Vladimir regions; foci have been noted in the Republic of Mari El. During outbreaks of mass reproduction, the number of individuals of the weaver sawfly can reach very high values. The ability to fall into a long diapause, sometimes lasting 3 years or more, often leads to the formation of chronic foci, in which, due to the high number of individuals, severe crown defoliation occurs for several years. In the formed and active centers of mass reproduction of the weaver sawfly, weakening, severe thinning and death of pine plantations occur. Carrying out measures to localize and eliminate phytophage foci is associated with certain difficulties: long periods of flight of adults and damage to crowns by larvae, development of larvae in a web nest. Each year, only one part of the population is reactivated, while the other part may remain in a state of diapause. All this is extremely important to take into account when obtaining the most accurate and complete information about the abundance and condition of phytophage populations in each forest area where its increased abundance is noted. Such information can be obtained only as a result of reconnaissance and detailed forest pathological examinations, laboratory analyzes of the collected eonymphs and pronymphs. When conducting forest pathological monitoring of populations of the weaver sawfly, the following requirements of the generally accepted standard system of forest protection measures should be met: observation of the appearance (operational detection) and mass distribution (survey), data collection, measurements and accounting; four

5 data analysis and assessment of the observed situation based on the dynamics of indicators, forecast of the development of the situation, adoption of managerial and technological decisions; carrying out measures to regulate the population, assessing the effectiveness of forest protection measures. This brochure was prepared by Yu. I. Gninenko in order to fulfill the planned task under the supplementary agreement to the State Contract dated З-9К-11/4. Research was also carried out as part of the scientific work of VNIILM and the Volgograd branch of Roslesozashchita by a graduate student of VNIILM, head of the forest protection and forest pathological monitoring department of the Forest Protection Center of the Volgograd Region. G. A. Gray under the direction of the head. laboratory of forest protection from invasive and quarantine organisms VNIILM Yu. I. Gninenko. The Senior Consultant of the Department of Forest Protection and Protection of the Forestry Department of the Ministry of natural resources Volgograd region E. Yu. Bondarenko. Photo materials of the authors are used in the Guide. Photo of an adult yellow-headed weaver sawfly (Fig. 8) D. Simonchuk. 5

6 Weaver sawflies of the genus Acantholyda Currently, more than 50 species of weaver sawflies of the genus Acantholyda Costa, 1894 (Hymenoptera, Ramphiliidae) are known. Most of them live in North America, a small part in the northern part of Eurasia. On the territory of Russia there are 5 species of this genus, developing on conifers Oh. Some of them are mass pests. Among the weaver sawflies of this genus, the red-headed weaver sawfly Acantholyda erythrocephala Linneus, 1758 (Fig. 1 5) was the most well known as a pest. It forms centers of mass reproduction in young pine forests, usually growing on sandy and loamy soils in many countries of Europe and Asia. The largest centers operated in the European part of Russia at the beginning of the second half of the 20th century. So, in the Volgograd region. since the early 1960s. Until 2014, the foci of this weaver sawfly occupied an area from 0.2 thousand ha to 7.9 thousand ha. In the Voronezh region from 1958 to 1962, foci of this species covered areas from 9.9 thousand ha to 16.8 thousand ha. Smaller foci were also observed in the Rostov, Saratov and Orenburg regions. Information on the area of ​​foci of this pest species in Russia over the past 9 years is given in Table. 1. Table 1. Centers of mass reproduction of the red-headed weaver sawfly in Russia in the years. Region (region, krai) Area of ​​outbreaks, ha, by years Voronezh,5 0.5 Volgograd Rostov Stavropol on an area of ​​5 hectares, in 1962 in Omsk on 14 hectares, in the Kurgan region. on 127 ha. in the Kurgan region. in 1963, the outbreak was reduced to 59 ha, and remained on the same area in 1964 and 1965. By 1966, the area of ​​the outbreak had decreased to 39 ha, in 1967 and 1968. she hasn't changed. In 1964, outbreaks on an area of ​​13 hectares were noted in the Krasnoyarsk Territory. In the Omsk region in 1965, outbreaks were active on an area of ​​6

7 40 ha, and in 1966 by 67 ha. At the same time, red-headed and stellate weaver sawflies were found simultaneously in the foci. Large foci of the star sawfly-weaver formed in the Altai Territory in 1969 on an area of ​​137 ha. In 1970 they continued to operate, but in 1971 the foci faded. Sometimes joint centers of mass reproduction of red-headed and star-shaped weavers were formed, as was the case, for example, in the 1990s. in the Krasnoyarsk Territory and some forestry enterprises of the Kurgan Region. In 2013, on the territory of the Borsky district forestry of the Voronezh region. foci were detected on an area of ​​20 hectares. A solitary weaver sawfly, Acantholyda herogliphica Christ, is a well-known pest of young pine plants. However, this species rarely forms centers of mass reproduction. It usually damages single plants at the age of 3–5 years (Figs. 6 and 7), sometimes it accompanies other sawflies in the centers of their mass reproduction. For the entire period of observations in Russia, only in 1963 was a focus of this sawfly recorded on an area of ​​15 hectares in Tomsk oblast. The yellow-mouthed weaver sawfly Acantholyda flaviceps Retzius, 1783 (Fig. 8) is widespread in Russia; however, in most regions within its range, its individuals are very rare. In this regard, this species was included in the red books of some regions. Russian Federation, in particular the Murmansk region. However, in 1995, in a cedar stand near the town of Kolpashevo (Tomsk region), on an area of ​​about 100 hectares, a center of its mass reproduction was discovered. This focus has been active for more than 15 years, and weaver larvae regularly cause significant damage to cedar plantations. The area of ​​outbreak of yellow-mouthed weaver sawfly in the city is given below: Year Area, ha Year Area, ha Year Area, ha

8 Having reached its maximum area in 2007, the outbreak continues to operate within this area until now. The presence of a chronic center of mass reproduction of the yellow-mouthed weaver sawfly emphasizes the groundlessness of its inclusion in the Red Book of Russia. The larch sawfly Acantholyda laricis Giraud, 1861 is found in larch forests, which, however, is not a mass pest and is quite rare within its range. In the Urals, an outbreak of mass reproduction of this sawfly was observed, but nowhere else was its high abundance recorded. Of the weaver sawflies of this genus, the star weaver sawfly Acantholyda posticalis Matsumura currently deserves the most attention. In recent decades, it has formed the largest centers of mass reproduction of all representatives of this genus. Its foci were previously recorded only in southern regions European part of the country and in the south of Western Siberia. However, in recent years, outbreaks have been active in the Tver and Vladimir regions. They are found in Estonia and Finland. This makes it probable that weaver sawfly outbreaks were found in the Leningrad, Novgorod, Pskov regions and in Karelia. eight

9 BRIEF INFORMATION ON BIOLOGY AND MORPHOLOGY Acantholyda posticalis Mats. (syn. A. stellata Christ., Lyda stellata Chr., L. nemoralis Thoms., L. pratensis F., L. pinivora Enst.) is a widespread dangerous pest of Scots pine. The Palearctic species is distributed in the European part of Russia almost everywhere in the pine area, with the exception of the northernmost regions. In northern Asia, it is found approximately south of the 64th parallel to the border of the range of Scots pine. Information about the laying of eggs by the weaver sawfly on cedar, spruce and fir is doubtful or based on random observations. The wings of adult males and females are transparent, grayish towards the top. The head and thorax are black with yellowish-white spots that vary greatly in shape and brightness. The abdomen of the female is rufous with a darkened dorsal stripe along the median line (Figs. 9 and 10), while that of the male is dark (Fig. 11). Body length mm. Larva (false caterpillar) without abdominal legs, only the 10th segment bears a pair of cerci. The body of the larva is olive-green in color with 3 longitudinal brownish stripes along the back and abdomen, both lateral ones look like stripes torn into spots (Fig. 12). Head brown-yellow with darker dots. Legs and cerci are silver-brown with light articulations. Body length mm. Male larvae molt 4 times and go through 5 instars. The larvae of females molt 5 times, passing through 6 instars, and differ in the width of the head capsule, respectively, 0.9; 1.1; 1.5; 1.8; 2.1; 2.5 mm. Pronymphs may be yellow, orange-yellow or yellowish-green, in different populations individuals of different colors may predominate (Fig. 13). Head and occipital shield brown. Leg segments darkened. During the formation of the pupa, the pronymph is somewhat enlarged and has a thin cover (Fig. 14). The pupa is pale yellow, darkens with time (Fig. 15). Boat-shaped egg 2.6 mm long (Fig. 16). Adults fly in May June. The female lays eggs along the periphery of the entire crown on the surface of the needles of previous years, one egg at a time, rarely more. Female fecundity up to 50 eggs. Unfertilized eggs develop, but only males emerge from them. Egg incubation lasts 9-14 days. A freshly hatched larva crawls to the nearest May shoot and, in the axils of the needles, braids a loose cobweb nest, which compacts as it grows. Each young larva lives in 9

10 separate spider nest. After two molts, she still feeds on the needles of the shoots of the current year, first eating it from the edges, and then gnaws it, leaving stumps of various lengths. Starting from the third age, the larvae can feed on the needles of previous years. It is assumed that feeding on needles of different years is the reason for the occurrence of a long diapause in this species. When feeding, each larva braids a new independent cap in the form of a long web tube. Feeding, the larva protrudes from it, bites the needles, drags it towards itself and eats it, leaving only the tip. The tube, as a rule, is not contaminated with either needle residues or excrement (except when lumps of excrement falling from above get stuck). However, by the end of feeding, a large amount of excrement sometimes accumulates in the spider nests, which makes such nests well visible. Feeding lasts no more than a day, but due to the extended flight of adults, larvae in the crowns are found for 1 1.5 months. In the first half of July, the larvae fall from the tree onto the forest floor and burrow into the soil, arranging a cradle in it (usually at a depth of 5 to 20 cm). In the cradle, the body of the caterpillar becomes yellow, orange-yellow or pale grass-green. The prepupal period in the life of the star sawfly weaver, like other sawflies, is divided into 2 stages. The first stage, when the caterpillar has only changed its body color, is called eonymph. Eonymph has a black larval eye. As soon as it leaves the state of diapause (reactivates), its ocellus becomes somewhat clarified, dark spots of imaginal eyes appear above the larval ocelli, corresponding to the compound eye of the pupa and then the adult insect. Such reactivated caterpillars are called pronymphs. It is easy to divide the inhabitants of soil cradles according to the degree of development of the disks of the imaginal eyes, starting from the end of August. Usually, the process of reactivation ends by mid-September throughout the entire range of the phytophage. Pronymphs will emerge from pronymphs in spring, while eonymphs will continue diapausing. Diapause can last from 1 to 7 years, and the number of adults emerging from the soil varies annually: from single to almost all individuals. Most of the life of the imago of the star weaver is spent in the crowns of trees, in warm sunny days males are very mobile, females are calm. When counting adults in the crown, various 10

12 12 OUTBREAKS OF MASS BREEDING OF THE STAR SAW IN THE USSR AND RUSSIA Outbreaks of mass reproduction of the star sawfly in the territory former USSR known since the beginning of the twentieth century. The first major outbreak was recorded in the Southern Trans-Urals. Forest Inventory Expedition, which in the years. worked on the territory of the Neplyuevsky forestry (near the city of Kartaly, Chelyabinsk region), the centers of the weaver sawfly were identified on an area of ​​19.1 thousand hectares. This was an unusual occurrence for that time. In 1929, the well-known entomologist G.S. Sudeikin arrived here specifically to study these foci. As a result of the surveys, weaver foci were identified in the Dzhabyk-Karagai forest on an area of ​​6.8 thousand hectares, in the Neplyuevskaya dacha 1.3 thousand hectares and in the Bredinskaya dacha 17.2 thousand hectares, i.e., on a total area of ​​about 44 .4 thousand ha. In addition, small foci also operated in Mogutovskaya (75 ha) and Zaakmulinskaya (140 ha) dachas, as well as in a number of small pine forests. The total area of ​​the outbreaks was about 45.0 thousand ha, and in most of this area the pines were eaten by larvae by more than 75%. These are the largest observed foci of the weaver sawfly in the Chelyabinsk region. Archival materials of the Bredinsky forestry show that the phytophage caused the first damage to pine trees in the southeastern part of the Bredinsky dacha (kv) on an area of ​​​​about 100 hectares back in the years. Severe damage to pine trees was also found in the Kozitsina grove in the years. Regular observations of the appearance of foci began in the second half of the 20th century. It has been established that the centers of the weaver sawfly are formed, first of all, in artificial young pine forests. Prior to this, relatively small foci were known in low-density old pine forests. The zone of outbreaks of mass reproduction of the star-shaped sawfly-weaver covers pine stands from the Rostov region. in the southwest of Russia to the Tver and Vladimir regions in the north of the country and Transbaikalia in the east, also capturing the entire northern part Kazakhstan. In 1913, a small number of

13 weaver-sawfly dancers. Since the 1960s outbreaks of mass reproduction of the red-headed weaver sawfly began to be regularly observed. In these foci, then there was an increase in the number of stellate weaver sawfly. In 2001, star weaver foci were identified on the territory of Bykovsky, Ilovlinsky, Svetloyarsky and Staropoltavsky forestries. In 2010, outbreaks appeared in Archedinsky, Kalachevsky, Mikhailovsky, Podtelkovsky forestries. A similar pattern of joint foci of weaver sawflies has been observed since 1963 in Bogucharsky, Donskoy, and Davydovsky forestries of Voronezh oblast. The largest centers of the weaver have been operating in the Altai Territory since the 1960s. until the end of the twentieth century. For a long time, a large weaver's hearth operated in the Priketsky forests of the Tomsk region, where N. G. Kolomiets conducted his main studies, who prepared an appropriate summary based on their results. However, this outbreak remains in fact the only major outbreak in the region, and such significant outbreaks have not occurred there again. One of the epicenters of the formation of foci of the star sawfly weaver in Siberia is young pine forests located in the south of the Chelyabinsk and Kurgan regions, as well as Altai Territory. Thus, in the Asian part of Russia, it is possible to distinguish a zone covering pine forests growing in the Southern Trans-Urals and the Altai Territory, where weaver foci operate over large areas. The pine forests of Omsk, the south of the Tyumen and Novosibirsk regions adjoin this zone. In fact, this zone also covers the pine forests of the Kustanai region. and tape forests of the Irtysh region in Kazakhstan. The star sawfly-weaver is one of the most dangerous pine pests in the belt forests of Kazakhstan. Thus, it can be stated that the cultivation of artificial young pine stands in the steppe and forest-steppe zones from Southern Urals to Altai contributes to the creation of conditions for the development of centers of mass reproduction of the stellate weaver sawfly. In a number of regions of the European part of the country (Volgograd, Rostov, Tver, Vladimir and other regions), Trans-Urals (Chelyabinsk and Kurgan regions), Western and Eastern Siberia(Omsk and Chita regions, Altai Territory) and Kazakhstan, there were large outbreaks of mass reproduction of the star sawfly weaver, which often turned into chronic foci 13

fourteen . In some years, the area of ​​the outbreaks reached several tens of thousands of hectares. The largest centers operated in the Volga region, in the forests of the Altai Territory and the Kurgan Region. In recent years, centers of mass reproduction have been identified in the Tver region; they have been operating for more than 12 years on an area of ​​515 thousand hectares. The star sawfly-weaver is able to form outbreaks of mass reproduction and to a large extent damage pine plantations over large areas, which often leads to thinning and drying out of artificial pine plantations. In natural pine forests, especially in middle-aged and older stands, weaver sawfly foci are rarely formed. At the beginning of the twentieth century. large population outbreaks are known in natural young pine forests in the Chelyabinsk region, when the phytophage developed in forest stands formed on the site of large burned areas. The first identified weaver foci in the Chelyabinsk region. covered natural pine forests of different ages (from young to maturing). Most often, the weaver sawfly forms centers of mass reproduction in artificial plantings of Scots pine over the age of 5 years, created on sandy or sandy loamy soils. The foci are almost always chronic and last for several years. Long-term damage to needles in chronic foci, in the absence or low effectiveness of protection measures, leads to the drying out of artificial plantations of pine (first of all, plantings created in conditions that do not correspond to the growth of pine die). Often, low-density artificial pine forests appear due to the impact of the sawfly. So, in the 1970s. We examined almost all pine stands that grew in the areas of the largest outbreaks at the beginning of the 20th century. in the Chelyabinsk region In those years, forest protection measures were not carried out, severe damage to pine crowns was recorded, but the pine forests did not die). Pine forests with a density of no more than 0.5 have been preserved everywhere in the place of the centers that have been in operation for years. Apparently, the mass reproduction of the weaver here led to the formation of such forest stands, which, in terms of their characteristics, most corresponded to local conditions. In some areas of the Archedinsky and Bykovsky forestries of the Volgograd region. centers of mass reproduction of stellate pi- 14

15 weavers formed in artificial plantations of pine at the age of one year (on an area of ​​5.0 and 1.3 ha). They are located in areas where the use of insecticides is prohibited by sanitary requirements and forest protection measures have not been carried out here. In the years larvae of the weaver sawfly caused severe damage to the plantations here, but special surveys carried out in the years found that the death of trees in both areas did not exceed the norm of natural mortality. In 2006, the weakening of pine stands as a result of damage by weaver larvae was noted on a total area of ​​10.5 thousand hectares in the Central and Siberian Federal Districts. Drying of plantations was revealed in the Tver (84 ha) and Vladimir (4 ha) regions. In 2007, drying out of pine forests as a result of crown defoliation in previous years was noted in Tver oblast. only 9 ha. In 2013 in the Vladimir region. in the chronic focus of the weaver, clear sanitary felling was carried out on an area of ​​about 40 hectares. Special observations of the state of pine at permanent observation points in the Chelyabinsk region. showed that after damage of varying intensity by larvae for several years, the proportion of drying and dead trees was 20-35% of the total number of trees. Outbreaks of mass reproduction of the star sawfly weaver can serve as an example of the influence of phytophages on the possibilities of afforestation in areas where the forest did not grow before. In Soviet times, in a number of areas Northern Kazakhstan, Altai Territory and other regions on non-forest areas in order to increase forest cover, pine forest plantations were created. From the age of 10 years and older, centers of mass reproduction of this phytophage appeared in them. The areas of outbreaks in the Semipalatinsk, Pavlodar and other regions of Kazakhstan, as well as in the Altai Territory, Kurgan and other regions reached many tens of thousands of hectares. So, in 1980, at the time of the greatest development of these foci, their area in the Kazakh part of the ribbon forests was more than 61 thousand hectares. It was just as great in the Russian part of the forests. These outbreaks have resulted in artificial pine stands created in non-forest areas either dying or being replaced by sparse pine forests. fifteen

16 Joint centers of mass reproduction of the weaver star sawfly with other sawflies An increase in the number of individuals of the weaver star sawfly is often simultaneously accompanied by an increase in the number of other pine sawflies. However, the scale of this phenomenon and the prevalence of such foci is currently difficult to determine. This is due to the fact that in the reporting documents, forest protection specialists indicate either the most widespread type of pest, or the type that they were able to identify. In addition, earlier the species of sawflies was not always correctly determined. Despite such errors, it can be said with certainty that several cases of simultaneous development of an outbreak of mass reproduction of the stellate weaver sawfly and other sawflies are known (Fig. 17). For example, foci of star-shaped and red-headed weavers were repeatedly recorded. However, during the formation of foci, these species have a pronounced preference for certain soil conditions. Thus, the foci of the star-shaped sawfly-weaver are preferably formed on sandy, sandy-loamy and greasy soils, while the foci of the red-headed sawfly-weaver are formed on sandy and loamy soils. Both species very slowly develop new areas of pine forests, have similar biology (this increases interspecific competition) and common entomophages. In this regard, usually such common foci do not persist for a long time. Foci, in which an increased number of star and red-headed weavers, red pine sawfly, common pine sawfly and other species were simultaneously recorded, were observed in pine forests of Volgograd oblast. In this region, apart from weavers, other species of sawflies formed foci independently. Most often, these were the red or common pine sawfly, but sometimes other species also formed foci (Table 3). The presence of centers of mass reproduction of several species at once significantly complicates the work of forest pathologists. When determining the degree of threat to the photosynthetic apparatus, it is necessary to conduct counts of the number of wintering individuals of each of the identified species separately, determine the state of their populations, and

17 then determine the threat posed by each species individually. Summing up the threat from each species, it is necessary to obtain an integral threat of possible defoliation in such foci. There are a number of features in carrying out measures to localize and eliminate foci of pests. In their implementation, one should focus on the most numerous species. It should be remembered that the duration of the treatment should be chosen so that the drug can cause the death of larvae of all species. In practice, this is difficult to achieve, since some types of pests different dates start of larval development. In this case, it is necessary to provide a different processing technology in the foci. Table 3. Centers of mass reproduction of sawflies in pine forests of Volgograd oblast. Species name Acantholyda posticalis Mats. Red-headed weaver sawfly Acantholyda. L. Red pine sawfly Neodiprion sertifer Geoff. Common pine sawfly Diprion pini L. Pale-footed pine sawfly Microdiprion pallipes Fallén Similar pine sawfly Diprion similis Hartig Greenish pine sawfly Gilpinia frutetorum Fabr. Yellowish pine sawfly Gilpinia pallida Klug. The period of action of the foci From the beginning of the XXI century. to the present From 1960 to the present From the middle of the 20th century to the present from the middle of the twentieth century. to date Average area of ​​foci over the years of observations, ha yy yy yy 20 Effective biological preparations for protection against weaver sawfly larvae do not currently exist. 17

18 MEASURES FOR LOCALIZATION AND ELIMINATION OF FOCI OF THE STAR SAW WEaver Measures for the localization and elimination of foci of insect pests are a sequential chain of types of work on the treatment of plantations using an appropriate set of machines and devices, treatment methods (ground or air) using biological and chemical preparations or other methods . To protect pine forests from damage caused by the larvae of the star sawfly weaver, aerial or ground spraying is usually carried out with special preparations. The first protective treatments in the centers of the weaver were carried out in the middle of the 20th century. with the help of drugs such as DDT and hexochloran. Later, chlorophos and other organophosphorus preparations were widely used, then various pyrethroid preparations. However, due to the peculiar biology and phenology of the insect pest under consideration, it is difficult to achieve a satisfactory result of the treatments. Pyrethroid preparations, when applied once, do not always provide high efficiency, since it is difficult to spray so that all weaver individuals are under the influence of the drug. During early processing, some of the adults have not yet completed egg laying; with a later processing time, some of the larvae have time to finish feeding and go into the soil. In recent years, positive experience has been accumulated in the reliable protection of pine forests from pests using Dimilin, SP 250 g/kg. In this case, it is possible to carry out a single spraying on the pest's egg-laying. As a result of the use of this drug in the foci of the phytophage in the Tver region. in 2006, % of feeding larvae died. After the completion of feeding, the death of larvae continued. In the spring of the following year, the death of pronymphs during pupation and during the formation of adults was noted. It should be remembered that to protect the forest from pests, only those insecticides that are included in the State Catalog of Pesticides and Agrochemicals Permitted for Use on the Territory of the Russian Federation, published in the year of measures to localize and eliminate foci, should be used. At the same time, experience shows that it is rather difficult to obtain a reliable result of protective treatments against the weaver. In Che-18

19 Lyabinsk region a single aviation spraying or aerosol treatment with Decis, EC (consumption rate of the drug 0.08 l/ha) ensured the death of % of larvae. Only with an increase in the consumption rate of the drug to 0.3 l/ha, the mortality rate reached 95% of the number of larvae (G. I. Sokolov, personal communication). A similar situation developed in the center of the star weaver in the Maksatikha forestry enterprise, Tver oblast. Single treatments with Decis, EC, the consumption of which corresponded to the norm recommended in the State Catalog, did not give results. Despite the ongoing treatments, the pest larvae continued to cause severe damage to a significant part of the outbreak area. In subsequent years, measures to protect the forest in this focus were carried out only with the use of the insecticide Dimilin, SP 250 g/kg. Aerial spraying was carried out at a time when the bulk of the females had completed oviposition and in the crowns there were mainly eggs of the pest and partially larvae of 1–2 instars. This strategy made it possible to obtain a high efficiency of treatments (Table 4) and to prevent the expansion of the focus area. Indeed, despite the fact that in 2001 and 2003. the main part of the population emerged, the larvae did not cause severe damage to the crowns of pines, and the area of ​​the outbreak did not increase. Table 4. Technical effectiveness of aviation protection measures carried out in the Maksatikha forestry Year Area of ​​treatment, ha Preparation Decis, EC 25 g/l Dimilin, SP 250 g/kg Dimilin, SP 250 g/kg Phenological period of treatment Technical efficiency, % Larvae 2 4 instars< 30 Яйцекладки и личинки 1 2 возрастов Яйцекладки и личинки 1 возрастов 90,0 88,5 В гг. в действующих очагах хвое- и листогрызущих вредителей (в том числе и в очагах пилильщиков-ткачей) на территории Волгоградской обл. были проведены опытно- производственные обработки с использованием Димилина, СП 250 г/кг и разработаны соответствующие технологических схемы. В результате использования данного препарата в сочетании с выбранными технологиями в дальнейшем отмечалась значительная гибель пилильщиков-ткачей. Исключение составили отдельные случаи обработок с низкой эффективностью из-за нарушений их технологии. 19

20 The main reason for the low effectiveness of treatments against the weaver sawfly is that due to the strongly extended flight of adults and their laying of eggs, adults, eggs and larvae of different ages are simultaneously in the forest stand. Usually protective treatments are started when most of the larvae have hatched from eggs. However, at this time, a significant part of the weaver sawfly larvae complete feeding and leave the effects of the drug or, being in their last instars, become very resistant to them. It should be noted the role of the web nest of larvae, which prevents direct contact of the larvae with the insecticide. With a high number of weaver sawfly, 2-fold treatments give the best effect. The first spraying should be carried out at the time when the main part of the females flew out, and in the forest stand there are already larvae of 1-3 instars, hatched from the eggs of the first females that have flown out and the oviposition of females that have flown out later, and some of the females are just finishing their emergence from the soil. This treatment destroys larvae that hatch early. Then, approximately 7-10 days after the first treatment, it is necessary to re-spray, which will destroy the larvae that hatched later. However, such a method of carrying out protective measures is unacceptable for two reasons, the cost of work increases significantly and 2-fold processing is not provided for by the State Catalog. The most effective protection of pine forests from the weaver sawfly is a single treatment with Dimilin, SP 250 g/kg. They should be started when the flight of adults is not yet completed, and in forest stands, most of the phytophage population is in the stage of oviposition and larvae of younger ages. The most common mistakes that are the reasons for reducing the effectiveness of measures to localize and eliminate foci of forest pests are usually found at the design stage and directly during the organization and conduct of the activities themselves: unreliable data from forest pathological surveys and poor-quality forecast of the situation; non-compliance with the method of accounting for the number; underestimation of the biological characteristics of insect pests, parameters of forest plantations and working areas; violation of technology during treatments associated with the choice of insecticide, its preparative form, norm 20

22 FOREST PATHOLOGICAL SURVEYS The purpose of operational forest pathological surveys or verification of signaling materials is to verify information about the detection of an increase in the number of weaver sawfly. Such examinations are carried out during the feeding period of the larvae and after its completion, according to the damage caused and the nests remaining in the crowns. The preferred calendar date for such surveys is from the end of June to the beginning of August. It was during this period that damage caused by larvae and spider web nests with excrement remaining in them are most noticeable in the crowns. Surveys can be carried out later, but the later they are started, the less noticeable are the spider nests with excrement, as they are destroyed by rain and wind. Surveys of pine forest stands, in which an increase in the number of weaver sawflies is possible, are carried out during a visual inspection of forest areas on specially selected route passages. They must cross pine plantations and, above all, young pine stands aged 10 years and older. The basis for planning the route is detailed surveillance data (if, according to these data, an increase in the number of star sawfly-weaver is noted on the territory of the forestry or part of it) or forest pathological signaling data that revealed the presence of damage to pine forests on the territory of a particular district forestry. When laying the route, a list of forest areas is compiled, in which, according to the available information (signalling sheets or other forest pathological signaling data), the presence of damage is noted or an increase in the number of weaver sawfly populations is possible (forest pathological monitoring data). During the examination, the specialist fills in the log of the results of the operational examination (Appendix 1). If the state of a particular stand is visually the same, then it is sufficient to assess the state of the crowns on one temporary accounting site. If the allotment differs in that in some parts of it damage to trees is significant, and in other parts it is hardly noticeable or not noticeable at all, then in such a allotment, an assessment of the state should be carried out on 2 3 accounting areas - 22

23 kah. In this case, the area of ​​the taxation unit is divided into several forest pathological units. The result of the conducted surveys is information on the presence of damage, their location and area, as well as preliminary (probable) data on the number of pest individuals. Based on this information, no later than the beginning of September, a plan for the implementation of detailed forest pathological surveys for each district forestry and a consolidated forestry plan are drawn up. Current forest pathological survey Current forest pathological surveys are carried out in order to establish the area and boundaries of the weaver sawfly outbreaks, to establish its abundance, the state of populations and the threat to forest stands. In the foci of the stellate weaver sawfly, surveys should begin no earlier than mid-September and end no later than mid-October. The timing of the start of surveys is due to the fact that by mid-September the process of reactivation of eonymphs is completed everywhere and it is possible to establish with a high level of reliability the proportion of individuals that will pupate next spring and adult insects will fly out of them. Until mid-September, the process of reactivation of eonymphs continues, and the results of the survey will not provide reliable information about the real threat to pine crowns in the early summer of the next year. The survey is carried out in those sections where the operational forest pathological survey revealed overeating of crowns by more than 20% of the number of trees. Detailed forest pathological examination and determination of the number of individuals of the weaver sawfly A detailed forest pathological examination is carried out in the identified weaver foci. Its main goal is to determine the number of individuals in the soil, to establish their condition and, on this basis, to predict the reality of the threat of damage in order to make a decision on taking measures to localize and eliminate the outbreak. The survey is carried out from the second half of September until the establishment of a stable snow cover. 23

25 The minimum number of survey ditches in each section 3. The number of survey ditches can be increased in case of large differences in the number of individuals in each excavation and, if necessary, to obtain more accurate results. According to the records, the average number of weaver pronymphs and eonymphs per 1 m 2 of the soil surface is derived. This indicator is further used to determine the degree of threat to the forest stand. All specimens of the weaver sawfly collected in one section should be placed in one container (it is advisable to use soil bottles, plastic jars or special wooden boxes for this). A label is stuck on the container (you can put it inside) indicating the place of collection and the date of the examination. Soil should not be placed in a container with phytophage specimens, since during transportation it can damage eonymphs and pronymphs. Individuals of the weaver sawfly collected during examinations should be immediately (preferably on the first day) delivered to the laboratory and placed in a refrigerator with a temperature of +4 +6ºС. Long-term storage of collected weaver sawfly specimens outside the refrigerator is unacceptable, as they deteriorate very quickly, and laboratory analysis of such specimens is often impossible. Detailed examinations of the foci should be planned in such a way that the delivery of specimens to the laboratory is ensured no later than in 2-3 days. after the excavations. Determining the state of the forest stand The state of the forest stand in the center of mass reproduction of the weaver sawfly should be determined by the crown of pines. In this case, the main attention should be paid to the crown foliation, since previous damage can greatly reduce the mass of needles in the crowns (Fig. 19). In the surveyed areas, the state of the forest stand can vary greatly depending on the damage caused earlier by phytophage larvae. Often, the foci of the weaver sawfly are chronic, and the pest can damage the crowns several times. Therefore, in order to calculate a reliable possible threat of crown eating, it is necessary to know the condition of the trees in each specific surveyed forest area. To obtain such information during a detailed forest pathological examination, an eye examination should be carried out.

26 a dimensional assessment of the condition of the crowns, indicating the percentage of their actual foliation compared to the normal foliation of pines growing in similar conditions and not subjected to phytophage eating in previous years. To do this, it is necessary to evaluate the crown foliation of at least 50 trees and calculate the average value of foliation in a particular allotment. The results of accounting for the state of pine crowns in the centers of the weaver are entered in the statement (Appendix 3). In order to conduct such an examination, a specialist must, in the order of training, visit several areas of pine forests that have not been damaged earlier of the same age and quality class. This is important in order to visually assess the scale of the complete crown foliation. When examining the forest stand in the outbreak, it must be remembered that visually less than 20% damage to the crowns is poorly distinguishable. Therefore, in the process of assessing the condition of the crowns, the specialist notes the first visible signs of damage, this will be the level of approximately 20% crown eating. It should also be remembered that 100% destruction of needles is extremely rare. Even in foci with a very high number of phytophage larvae, stumps or bunches of needles on individual branches remain in the crowns, etc. After damaging the next year, the tree, as a result of its weakening, will not be able to grow as many needles as it would have grown in the crown if the damage had not been inflicted. Special studies have shown that when about 30% of the photosynthetic apparatus is destroyed, a tree in the spring is able to fully restore these losses, and there are no problems with a decrease in the mass of new needles. When destroying a more significant part of the crown, this does not happen. Therefore, when determining the degree of threat, we suggest using the following margins: The degree of damage to the crown in the autumn of the year of the survey, % Crown foliation in the spring of the next year, %

27 According to the results of excavations, analysis of the state of phytophage individuals and taking into account previous damage, it is possible to establish the threat of expected damage to the crowns. Spring control forest pathological survey During winter, the number of pronymphs in the soil often changes, caused by their death from diseases or destruction by predators. In addition, a certain part of the females die during the flight (or scatter to other parts of the forest), and some of the eggs they lay on the needles in the crowns also die. Therefore, it is possible that the forest protection measures planned in autumn may not be in demand. In this regard, in each site planned for protective treatments, it is necessary in the spring, but no later than 2 weeks. before the scheduled date of work, to conduct a spring control forest pathological examination of oviposition in the crown. Such surveys should be planned in the autumn of the previous year, after the areas where protective treatments are planned have been identified. Spring control surveys should be started when at least half of the females have laid eggs. It can be very difficult to determine this period, since the flight of adults is extended and is often interrupted by the onset of normal spring period cooling. To determine the timing of this survey, one site is selected on the territory of the district forestry, in which the conditions of pine growth can be considered approximately corresponding to the majority of sites to be surveyed. On such a site, regular monitoring of the beginning of the flight of adult individuals of the weaver is carried out. To do this, from the beginning of May, every day at about the middle of the day, this site should be visited and the appearance of adults on the butt parts of pines should be monitored first by males. From the moment of the appearance of the first individuals of males, no later than after 5-7 days. excavate the soil and determine whether there are female pupae in the soil. If the pupae of females are few or absent, then the next day you should start counting eggs in the crowns of trees. Usually, by the time the last 10% of the females hatch, the females that have flown out earlier complete the laying of eggs, and larvae may already begin to hatch from the very first eggs laid. The calendar dates for the start of the spring follow-up examination usually fall on the period from mid-May to early June. 27

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The weaver sawfly is a large family of the order Hymenoptera. These insects are distributed throughout Eurasia and North America. Weaver sawflies damage coniferous trees.

Features of the appearance of the sawfly weaver

All types of weaver sawflies grow up to 10-15 millimeters in length. Adults have 3 pairs of legs and flagellar antennae. Each foot has a tooth. On the head are movable crescent-shaped mandibles. Their wings are transparent, membranous, with a well-marked network of veins. Wings fold horizontally. There are spurs on the legs. The larvae do not have ventral legs, but have developed pectoral tarsi. There are antennae on the head.

Varieties of sawfly weavers. Star sawfly weaver

This insect has a black breast and head with white and yellow spots. The wings are transparent, veins are visible on them.

Females are larger than males: the body length of female weaver sawflies varies from 12 to 16 millimeters, and males - from 10 to 12 millimeters.

The body is olive green with brown stripes. The pupa of the star sawfly weaver is yellow-white, shiny. The larvae reach a length of 25 millimeters. The larvae have 6 black pectoral legs.

Red-headed Weaver Sawfly

The body of these sawflies is wide, flattened on the sides. The wings are almost black with veins characteristic of all sawflies. The females have a bright red head, while the males have only the front of the head that is red, while the back is yellow.

The larvae of the red-headed weaver sawfly have green pectoral feet. Throughout the body there are longitudinal brown stripes, there are also subtle spots.

The head is yellow-brown.

Single sawfly weaver

The head, abdomen and thorax of a solitary weaver sawfly are black and yellow. The body length is 13-18 millimeters. The wings are transparent, light yellow, with veins.

The larva of a solitary weaver sawfly is dirty green. The larva has 3 pairs of thoracic legs and 1 pair of false legs, they are located on the last segment of the body.

The head is green-brown. The body length of the larva reaches 25 millimeters.

Weaver sawflies are pests of conifers: spruces and pines.

Yellowmouth weaver sawfly

The head and breast of the yellow-mouthed weaver sawfly are black, and the abdomen is yellow-brown.

oral apparatus bright yellow, hence the name. The wings are transparent with characteristic venation. The larva is 18-22 mm long. The body is yellow-orange and the head is black.

Weaver sawfly breeding

Larvae for wintering go underground, burrowing about 30 centimeters. In April-May, the larvae molt and turn into pupae. Adults appear after 10-13 days.

The flight of weaver sawflies lasts about 3-4 weeks, during which time adults mate.

The females lay their eggs on needles. The average fecundity of one weaver sawfly is 40-60 eggs. The eggs develop over 2 weeks, then the larvae hatch.

Caterpillars of sawflies have partial parthenogenetic reproduction - females emerge from fertilized eggs, and males from unfertilized ones. The larvae build a common nest from the web. They wrap their webs around the branches of the needles. Adult larvae make separate cases from the web. The larva develops for about a month, during which 6 instars pass. At the last stage, the larva feeds openly and no longer hides in a cobweb cover.

In summer, the larvae descend to the ground and make pits with dense walls there.

CONTENT

INTRODUCTION

Research methodology

The history of the development of centers of mass reproduction of the sawfly-weaver stellate

Damage from damage to plantings by the stellate weaver sawfly

The timing of the treatment of the focus

CONCLUSIONS

CONCLUSION

3-4

5-10

10-15

15-25

24-27

27-30
31

32-33

INTRODUCTION

Saw-weaver stellate -Acantholyda nemoralis, isone of the widespread pests of pine stands in Russia. The centers of its mass reproduction often cover large areas of young pine stands in a number of regions of the European part of the country, in the southern Trans-Urals, in the south of Western Siberia, in the Altai Territory and Transbaikalia. He is also a frequent visitor to the territory of the Volgograd region.

During outbreaks of mass reproduction, the number of weavers can reach very high values, which leads to significant damage to the crowns. The ability to fall into a long diapause, sometimes lasting 7 or more years, often leads to the formation of chronic foci, in which a high number of weaver individuals ensures strong crown defoliation for several years in a row.

All this weakens the forest stands in which centers of mass reproduction of the weaver have formed and operate, leading to the death of pine stands or severely thinning them out.

Carrying out measures to localize and eliminate weaver foci is associated with certain difficulties. This is due to the long period of flight of adults and the long period of damage to the crowns by the larvae. Each year, only a part of the population is reactivated, while a certain part of it may remain in a state of diapause. All this makes it extremely important to obtain the most accurate and complete information about the number and condition of weaver populations in each forest area where its increased number is noted.

It is possible to obtain such information only as a result of reconnaissance and detailed forest pathological examinations and laboratory analyzes of the collected eonymphs and pronymphs.

The relevance of the topic is related to the need to improve the efficiency of forest protection measures and improve the protection of forests from pests and diseases in the pine forests of the steppe zone.

The aim of the work was to study the center of mass reproduction of the stellate weaver sawfly, which appeared on the territory of the Archedinsky forestry.

The objectives of the research included:

to study the phenology and some other ecological features of the stellate weaver sawfly, including the dynamics of its abundance in the study area;

to evaluate the influence of the sawfly on the forage rock in the conditions of steppe pine forests;

obtain indicators for predicting the dynamics of the number of sawfly populations;

Carrying out measures to localize and eliminate weaver foci is associated with certain difficulties. This is due to the long period of flight of adults and the long period of damage to the crowns by the larvae. Each year, only a part of the population is reactivated, while a certain part of it may remain in a state of diapause. All this influenced the need to obtain the most accurate and complete information about the number and condition of weaver populations in each forest area, where its increased number was noted.

Literature review

1.1. Outbreaks of mass reproduction of the stellate saw-weaver in the USSR and Russia

P star-weaver or weaver -Acantholyda nemoralis, systematic position -Order Hymenoptera -Hymenoptera, a family of sawflies-weavers -Pamphiliidae.

A pest of pine plantations. Distributed in the Volga region, Altai Territory, Chelyabinsk, Tomsk and Chita regions, Kazakhstan, Ukraine and Belarus.

The centers of mass reproduction occur in high-density pine plantations of predominantly artificial origin at the age of 12-40 years, as well as in natural pine forests of middle and older ages related to white moss forests or their complexes with green mosses. Outbreaks of mass reproduction are protracted and often last 9-10 years or more. This is due to the presence of diapause and the slow action of the entomophage complex.

Outbreaks of mass reproduction of the star sawfly-weaver in the territory of the former USSR have been known since the beginningXXin. The first major outbreak was recorded in the Southern Trans-Urals. Forest Inventory Expedition, which in 1927-1928. worked on the territory of the Neplyuevsky forestry (near the city of Kartaly, Chelyabinsk region), the centers of the weaver sawfly were identified on an area of ​​19.1 thousand hectares.

This was an unusual occurrence for that time. In 1929, the well-known entomologist G.S. Sudeikin arrived here specifically to study these foci. As a result of the surveys, weaver foci were identified in the Dzhabyk-Karagay forest on an area of ​​6.8 thousand hectares, in the Neplyuevskaya dacha - 1.3 thousand hectares and in the Bredinskaya dacha - 17.2 thousand hectares, i.e., on the total area about 44.4 thousand hectares. In addition, small foci also operated in Mogutovskaya (75 ha) and Zaakmulinskaya (140 ha) dachas, as well as in a number of small pine forests. The total area of ​​the outbreaks was about 45.0 thousand ha, and in most of this area the pines were eaten by larvae by more than 75%. These are the largest observed foci of the weaver sawfly in Chelyabinsk region.

Archival materials of the Bredinsky forestry show that the phytophage caused the first damage to pine trees in the southeastern part of the Bredinsky dacha (square 113-114) on an area of ​​about 100 hectares back in 1901-1903. Severe damage to pine trees was also found in Kozitsina Grove in 1911-1915.

Regular observations of the appearance of foci began in the secondhalfXXin. It has been established that the foci of the weaver sawfly are formed,first of all, in artificial young pine forests. Before that they were knownrelatively small foci in low-density old pine forests.

The zone of outbreaks of mass reproduction of the star-shaped sawfly-weaver covers pine stands from the Rostov region in southwestern Russia to the Tver and Vladimir regions in the north of the country and Transbaikalia in the east, also capturing the entire northern part of Kazakhstan.

In pine young forests of the Archedinsky dacha (Volgograd region) in 1913, an insignificant number of weaver sawfly specimens were found. Since the 1960s, outbreaks of mass reproduction of the red-headed weaver sawfly have been regularly observed. In these foci, then there was an increase in the number of stellate weaver sawfly. In 2001, star weaver foci were identified on the territory of Bykovsky, Ilovlinsky, Svetloyarsky and Staropoltavsky forestries. In 2010, outbreaks appeared in Archedinsky, Kalachevsky, Mikhailovsky, Podtelkovsky forestries. A similar pattern of joint foci of sawflies-weavers has been observed since 1963 in the Bogucharsky, Donskoy, and Davydovsky forestries of the Voronezh region.

The largest centers of the weaver operated in the Altai Territory from the 1960s until the endXXcentury. For a long time, a large weaver's hearth operated in the Priketsky forests of the Tomsk region, where N. G. Kolomiets conducted his main studies, who prepared an appropriate summary based on their results. However, this outbreak remains in fact the only major outbreak in the region, and such significant outbreaks have not occurred there again.

One of the epicenters of the formation of foci of the star sawfly weaver in Siberia is young pine forests located in the south of the Chelyabinsk and Kurgan regions, as well as the Altai Territory.

Thus, in the Asian part of Russia, it is possible to distinguish a zone covering pine forests growing in the Southern Trans-Urals and the Altai Territory, where weaver foci operate over large areas. The pine forests of Omsk, the south of the Tyumen and Novosibirsk regions adjoin this zone. In fact, this zone also covers the pine forests of the Kustanai region and the ribbon forests of the Irtysh region in Kazakhstan. Star sawfly-weaver is one of the most dangerous pine pests in the belt forests of Kazakhstan.

Thus, it can be stated that the cultivation of artificial young pine stands in the steppe and forest-steppe zones from the Southern Urals to Altai contributes to the creation of conditions for the development of centers of mass reproduction of the weaver star sawfly.

In a number of regions of the European part of the country (Volgograd, Rostov, Tver, Vladimir and other regions), Trans-Urals (Chelyabinsk and Kurgan regions), Western and Eastern Siberia (Omsk and Chita regions, Altai Territory) and Kazakhstan, there were large outbreaks of mass reproduction of the star sawfly - weaver, which often turned into chronic foci. In some years, the area of ​​the outbreaks reached several tens of thousands of hectares. The largest centers operated in the Volga region, in the forests of the Altai Territory and the Kurgan Region. In recent years, centers of mass reproduction have been identified in the Tver region; they have been operating for more than 12 years on an area of ​​5-15 thousand hectares.

The star sawfly-weaver is able to form outbreaks of mass reproduction and to a large extent damage pine plantations over large areas, which often leads to thinning and drying out of artificial pine plantations. In natural pine forests, especially in middle-aged and older stands, weaver sawfly foci are rarely formed. At the beginningXXFor centuries, large population outbreaks have been known in natural young pine forests in the Chelyabinsk region, when the phytophage developed in forest stands formed on the site of large burned areas.

The first identified centers of the weaver in the Chelyabinsk region covered natural pine forests of different ages (from young to maturing). Most often, the weaver sawfly forms centers of mass reproduction in artificial plantings of Scots pine over the age of 5 years, created on sandy or sandy loamy soils. The foci are almost always chronic and last for several years. Long-term damage to needles in chronic foci, in the absence or low effectiveness of protection measures, leads to the drying out of artificial plantations of pine (first of all, plantings created in conditions that do not correspond to the growth of pine die). Often, low-density artificial pine forests appear due to the impact of the sawfly. So, in the 1970s, almost all pine stands were examined, which grew in the areas of the largest outbreaks in the earlyXXcentury in the Chelyabinsk region. In those years, forest protection measures were not carried out, the most severe damage to pine crowns was recorded, but the pine forests did not die. Pine forests with a density of no more than 0.5 have been preserved everywhere in the place of the centers that operated for 30-40 years. Apparently, the mass reproduction of the weaver here led to the formation of such forest stands, which, in terms of their characteristics, most corresponded to local conditions.

In some areas of the Archedinsky and Bykovsky forestries of the Volgograd region, the centers of mass reproduction of the star-shaped sawfly-weaver formed in artificial plantings of pine at the age of 23-42 years (on an area of ​​5.0 and 1.3 ha). They are located in areas where the use of insecticides is prohibited by sanitary requirements and forest protection measures have not been carried out here.

In 2010-2012, weaver sawfly larvae caused severe damage to plantations here, but special surveys conducted in 2013-2014 found that the death of trees in both areas did not exceed the norm of natural mortality.

In 2006, the weakening of pine stands as a result of damage by weaver larvae was noted on a total area of ​​10.5 thousand hectares in the Central and Siberian Federal Districts. Drying of plantations was revealed in the Tver (84 ha) and Vladimir (4 ha) regions. In 2007, drying out of pine forests as a result of crown defoliation in previous years was noted in the Tver region only on 9 hectares. In 2013 in Vladimir region in the chronic focus of the weaver, clear sanitary felling was carried out on an area of ​​about 40 hectares.

Special observations of the state of pine at permanent observation points in the Chelyabinsk region showed that after several years of damage by larvae of varying intensity, the proportion of drying and dead trees was 20-35% of the total number of trees.

Outbreaks of mass reproduction of the stellate weaver sawfly can serve as an example of the influence of phytophages on the possibilities of afforestation in areas where the forest did not grow before. In Soviet times, in a number of regions of Northern Kazakhstan, the Altai Territory and other regions, pine forest plantations were created on non-forest areas in order to increase forest cover. From the age of 10 years and older, centers of mass reproduction of this phytophage appeared in them. The areas of outbreaks in the Semipalatinsk, Pavlodar and other regions of Kazakhstan, as well as in the Altai Territory, Kurgan and other regions reached many tens of thousands of hectares. So, in 1980, at the time of the greatest development of these foci, their area in the Kazakh part of the tape forests was more than 61 thousand hectares.

It was just as great in the Russian part of the forests. These outbreaks have resulted in artificial pine stands created in non-forest areas either dying or being replaced by sparse pine forests.

The star sawfly-weaver is able to have a noticeable negative impact on the state of plantations.

Brief information about the biology and morphology of the pest

P star-weaver or weaver -Acantholyda nemoralis, widespread dangerous pest of pine (Vorontsov, 1959; Novikova, 1969, etc.).

Palearctic view. In the European part of the country, it is distributed almost everywhere in the pine area, with the exception of the northernmost regions. In northern Asia, it is distributed approximately from the 64th parallel (Ilyinsky, Tropin, 1965) to the south - to the border of the host plant. – Scotch pine (Kolomiets, 1967; Fedoryak, 1970). Information about the laying of eggs by a weaver on cedar, spruce and fir is doubtful, or based on random observations. The wings of adult males and females are transparent, grayish towards the apex (Fig. 1). The head and thorax are black with yellowish-white spots that vary greatly in shape and brightness. The abdomen is rufous with a darkened dorsal stripe along the median line. Body length 11-15 mm.

Fig.1. Imago of female (left) and male (right) star-shaped weaver sawfly

Caterpillar without ventral legs, only segment 10 bears a pair of cerci. The body of the larva is olive-green or grayish-olive in color with 3 longitudinal brownish stripes along the back and abdomen (Fig. 2), both lateral stripes broken into spots. Head brown-yellow with darker dots. Legs and cerci black-brown with light articulations. Body length 20-25 mm.

Rice. 2. Larva of star sawfly weaver

The pronymph is orange-yellow or grass-green; individuals of different colors may predominate in different populations (Fig. 3). Head and occipital shield brown. Leg segments darkened.

Rice. 3. Pronymphs (upper row) and eonymphs (lower row) of the star-shaped weaver sawfly

The pupa initially has the color of a pronymph, only somewhat paler (Fig. 4), but darkens with time.

Rice. 4. Pupa of star sawfly weaver

The egg is boat-shaped (Fig. 5), 2.6 mm long. Adults fly in May and June. The female lays eggs along the periphery of the entire crown on the surface of old needles one at a time, rarely more. Female fecundity up to 50 eggs. Unfertilized eggs develop, but only males emerge from them. Egg incubation lasts 9-14 days.

Rice. 5. Star Sawfly Eggs

A freshly hatched larva crawls to the nearest May shoot and in the axils of the needles braids a loosegossamer a nest that thickens as it grows. Young larvae each live in a separate web nest. After two molts, they still feed on the needles of the shoots of the current year, but with a lack of it, they feed on the needles of previous years. It has been suggested that feeding on needles of different years is the cause of a long diapause in this species. When feeding, each braids a new independent cover in the form of a long cobweb tube. Feeding, the caterpillar protrudes from it, bites the needles, drags it towards itself and eats it, leaving only the tip. The tube, as a rule, is not contaminated with either the remnants of needles or excrement (except when lumps of feces falling from above get stuck). However, by the end of feeding, a large amount of excrement sometimes accumulates in the spider nests, which makes such nests clearly visible. Feeding of each caterpillar lasts no more than three weeks, but due to the length of the adult flight, the larvae in the crowns occur within 1-1.5 months. In the first half of July, they fall from a tree onto the forest floor and dig into the soil, arranging a cradle in it (usually at a depth of 5 to 15 cm). In the cradle, the body of the caterpillar becomes yellow, orange-yellow or grass-green.

The prepupal period in the life of the star weaver, like other sawflies, is divided into two stages. The first stage, when the caterpillar has only changed its body color, is called eonymph. Eonymph has a black larval eye. As soon as the eonymph leaves the state of diapause (reactivates), its ocellus becomes somewhat clarified, dark spots of imaginal eyes appear above the ocelli, corresponding to the compound eye of the pupa and adult insect. Such reactivated caterpillars are called pronymphs (Fig. 4).

It is easy to divide the inhabitants of soil cradles according to the degree of development of the disks of the imaginal eyes, starting from the end of August. Usually, throughout the weaver's range, the reactivation process ends by mid-September. Pronymphs will hatch into adults in the spring. Diapause can last from 1 to 7 years; the emergence of adults from the soil is very different every year: from single to almost all individuals. Such prolonged diapausing leads to the formation of chronic foci of mass reproduction.

The flight of the star weaver is greatly extended, and in the forest at the same time one can observe winged insects, eggs, young caterpillars, caterpillars that finish feeding and diapausing eonymphs in the soil in the crown.

Thus, within one year, the stellate weaver sawfly develops in one generation (Table 2.1), but due to long-term diapause, part of the population can develop over 1, 2, 3 or more years.

Table 2.1. – Scheme of the annual development cycle of the stellate weaver sawfly

Note: E - eonymph; P - pronymph; K - pupa; I - imago; I am an egg; L is a larva.

The star weaver sawfly often forms foci together with the red-headed weaver sawfly, red and common pine sawfly (Fedoryak, 1970; Sery, 2008).

3. Research methodology

To obtain reliable data on the number of weavers during a detailed survey in sections 8, 9, 17 of the Archedinsky district forestry, soil excavations were carried out, the number of weaver individuals in the soil was counted, they were collected for further qualitative analysis populations in the laboratory.

When excavating the soil within the projection of the crowns of pines, soil pits were laid. Since eonymphs and pronymphs are not randomly located within the crown projection, but females predominate closer to the trunk, while males predominate further from the trunk, the soil pit was laid for the entire length of the crown projection from the trunk (i.e., equal to the crown radius) and had the width of a standard shovel bayonet (25 cm). The depth of the excavation did not exceed 15-20 cm. The area of ​​the crown projection was determined by the formula (1):

S = Lq, (1)

where

S– excavation area in m 2 ;

L– pit length (crown projection radius length), m;

q- the width of the pit (the width of the bayonet of a standard shovel) - 0.25 m.

During the excavations, all individuals of the weaver, cocoons and

In laboratory conditions, the number of individuals per 1 m was recalculated 2 , using formula (2):

N = n / S y (2)

where

N - number of individuals per 1 m 2 soil surface;

nis the number of weaver individuals in the counting pit;

S y– area of ​​the accounting pit in m 2 .

The number of accounting pits was laid down by 3 in each allotment.

After the weaver specimens were delivered to the office, they were analyzed. The purpose of this analysis was to determine the proportion of reacted individuals (pronymphs), the proportion of females, and the condition of females. This information is necessary to calculate the threat of needle-eating in the crowns in the first half of the next year.

Division of collections into eonymph and pronymph. In carrying out this analysis, all collected individuals were viewed using a magnifying glass. At the same time, eonymphs (not reactivated individuals) included those that lacked disks of imaginal eyes (Fig. 6).

Rice. 6. Head of a weaver (from N.G. Kolomiets, 1967): a) eonymphs; b) prepronymphs with incompletely formed imaginal eye disk; c) pronymphs with a fully formed imaginal eye disk.

These individuals remain in a state of diapause and their pupation and emergence as adults will not occur in the spring of the following year. Such individuals were not further taken into account when determining the threat of damage to crowns in the next year. Separation of pronymphs on the basis of sex. After separating individuals on the basis of reactivation, all pronymphs were divided into females and males. The main features for such a division was their size. The length and body weight of the female is greater than that of males (Table 3.1). Initially, all individuals were visually divided into females and males, putting the largest (females) in one direction, and the smallest (males) in the other (Fig. 7).

This preliminary separation greatly accelerated the analysis. Those remaining individuals, which were difficult to visually classify as small or large, were weighed and their head capsule width was measured. According to the results of such measurements and with a comparison of the data obtained with the data in Table 3.1, the individuals were classified as females or males.

Rice. 7. Female pronymphs (right) and males (left)

Table 3.1. – Differences between female and male star weaver sawfly

After establishing the proportion of females and males in each specific population living in each surveyed area, the number of females per 1 m2 was calculated. 2 soil surface to formula (3):

F = N· f / 100, (3)

where;

F- the number of females per 1 square. m (spec.);

N - the total number of pronymphs per 1 sq. m (spec.);

fis the proportion of females in the population (%).

The results of the surveys of the number of populations of the weaver star sawfly are shown in Table 3.3.

Table 3.2. – Qualitative state of the stellate sawfly weaver in the soil in the plantations of the Archedinsky district forestry

Sex ratio (female/male)

Number of analyzed individuals, pcs.

Status ratio

total number of individuals, %

viable

including reactivated

sick

68:32

89,9

The calculation of the expected overeating of needles was carried out according to the formula (4):

X =N· 100/K+(100-Y), (4)

where

X– expected crown eating(%);

N is the average number of healthy pronymph females per 1 sq. m of soil surfacespecific area;

K is a constant number equal to 18 (the number of healthy pronymph females threateningcomplete destruction of needles in the crowns of fully foliated crowns);

Y– average crown foliation on the site (%).

The state of the forest stand in the center of mass reproduction of the weaver was determined by the degree of crown foliation, since previous damage greatly reduces the mass of needles in the crowns. To obtain such information, an eye assessment of the condition of the crowns was carried out, the percentage of their actual foliation was indicated in comparison with the normal foliation of pines growing in similar conditions and not subjected to weaver eating in previous years.

Table 3.3. – The results of the conducted counts of the number and determination of the qualitative state of the populations of the sawfly-weaver stellate

1 m 2

soil

pronymph

initial

prodromal

1 m 2

soil

pronymph

initial

prodromal

1 m 2

soil

pronymph

initial

prodromal

1 m 2

soil

pronymph

initial

prodromal

1 m 2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

End of table 3.3

1 m2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

1 m2

soil

pronymph

initial

prodromal

To determine the state of the forest stand, the crown foliation of 50 trees was estimated and the average value of the crown foliation in a particular allotment was derived (Table 3.5). When determining the degree of threat, the following margins were used (Table 3.4).

Table 3.4. - Softness of pine crowns at different levels of previous damage

According to the forestry in 2013, 56% of trees without signs of weakening were recorded in the plantations, in 2014 the number of trees in this category decreased and amounted to 44%, and in 2015 the share of trees decreased to the level of 10%, while the condition category decreased. The redistribution of trees by condition category was noted annually.

The deterioration of the sanitary condition of plantings occurs under the influence of the complex adverse factors, the main of which were droughts over the past few years. Also, the impact on the sanitary condition of plantations is caused by damage to the crowns caused by the stellate weaver sawfly.

In 2015, a severe degree of damage was observed in the outbreak of the Archedinsky district forestry. Further defoliation, taking into account the threat of 100% overeating in 2016, would lead to their weakening and drying out, as a result of which significant environmental and economic damage would be caused.

Table 3.5. – Sanitary state of plantations of the Archedinsky forestry according to the forest pathological survey in 2016

In the event that measures were not taken to localize and eliminate the centers of mass reproduction of the pest, it was assumed that the outbreak would further spread to adjacent plantations in the territory of the forestry.

4. The history of the development of centers of mass reproduction of the stellate weaver sawfly

On the territory of the Archedinsky forestry, individuals of the stellate weaver sawfly were first noted in the 60s of the last century. Their presence was noted both singly and in focal numbers. The largest outbreaks of this pest in the territory of the forestry were noted in 1982 and 1990. From 2001 to 2010, there was a decrease in the areas of distribution of foci of this phytophage, and individuals of the pest were found in single specimens. Since 2010, there has been an increase in foci of star sawfly, which was recorded on an area of ​​76.1 ha in accepted plantations of former agricultural formations. In 2012, the areas of foci of this phytophage increased by 3.2 times. It should be noted that this pest is present in plantations, both in "pure" and in complex foci. In 2011, complexes of the stellate weaver sawfly with the red-headed weaver sawfly arose, where the colonization and damage to tree crowns by the last pest, in the period from 2011 to 2012, was below 25%. In 2014, the area of ​​foci of phytophages decreased by almost 2 times due to the measures taken for localization and elimination (1916.9 ha), as a result of which “pure” and complex foci of pests were eliminated. In 2015, treatments were carried out on an area of ​​520.8 ha, but due to the initially high abundance of the pest outbreak and a long diapause, an increase in the area of ​​outbreaks was noted in the plantations of the Archedinsky forestry. In 2016, on the territory of the forestry, the centers of the sawfly-weaver stellate operated on a total area of ​​1217.3 hectares.

In general, over the entire period of observations, the main factors in changing the dynamics of the pest population was a natural increase in the number of outbreaks of weaver sawflies, due to favorable weather conditions that have developed over a number of years (prolonged droughts).

Since 2011, an increase in the area of ​​foci of star sawfly has been noted on the territory of the Archedinsky forestry. Since 2013, in the plantations of the forestry, this phytophage has already been operating in combination with the red-headed sawfly, the number of the second is gradually decreasing due to partial or complete diapause. Since 2014, due to the prevailing favorable weather conditions and the release of the stellate weaver sawfly from partial diapause, there was an increase in the area of ​​foci of these phytophages, acting to a medium and strong degree in pine plantations of the forestry.

In 2010 and 2013, measures to localize and eliminate foci in order to reduce the number of stellate sawfly in the plantations of Archedinsky forestry were not carried out. In 2011 and 2012, treatments were carried out in the Frolovsky rural forestry on an area of ​​76.1 ha. Technical efficiency averaged62% and76.3%, respectively, as a result of which the foci of this pest were not eliminated. In 2014, activities for localization and elimination of foci were carried out on an area of ​​2241.7 ha in complex and “clean” phytophage foci. As a result of the treatments, the technical efficiency in the Archedinsky district forestry was 90.9%, in the Frolovsky rural forestry - 90.7%, in the Sosnovsky district forestry - 91.1% and in the Lyubimovsky educational forestry - 90.5%, and the pest outbreaks were liquidated. In 2015, measures to localize and eliminate outbreaks were carried out on an area of ​​337.6 hectares in complex and “clean” foci of the phytophage in the Archedinsky and Sosnovsky district forestries. As a result of the treatments, the technical efficiency in the Archedinsky district forestry and Sosnovsky district forestry was 91.0%, as a result of which the pest foci were eliminated.

Over the past three years, according to the forest pathological surveys of the Archedinsky forestry, there has been an increase in the number of stellate weaver sawfly from 34 in 2013 to 35 individuals in 2015. The occurrence of the phytophage in 2013 was 89%, in 2014 and 2015 it was in the range of 92-94%.

To calculate the threat of grazing on plantations by the larvae of the stellate weaver sawfly, the criterion for complete grazing of plantations was 35 pronymphs per 1 m 2 bedding. Table 5 shows the number of viable pronymphs per 1 m 2 soil. The calculation was made on the basis of survey data and indicators of the qualitative state of the population.

As a result of calculations, the threat of grazing plantings in 2016 from damage by the stellate weaver sawfly was 100%.

Often during the winter there is a change in the number of pronymphs in the soil, caused by their death from diseases or destruction by predators. In addition, a certain part of the females die during the flight (or scatter to other parts of the forest), and some of the eggs they lay on the needles in the crown also die. Therefore, in the first ten days of April, a control survey of the areas included in the focus of the stellate weaver sawfly was carried out. The predicted rate of overeating as a result of spring control was 93%.

According to the standard, the criterion for the appointment of measures for the localization and elimination of foci of harmful organisms is the total overeating of the crown, which should exceed 50%. In 2015, in these areas, there was severe damage to the needles, and the loss of needles was 35% or more.

By adding the percentage of defoliation from the star sawfly for 2015 and the predicted damage for 2016, this criterion was more than 128%. The current situation entails a decrease in growth and a general physiological weakening of plantations, and, consequently, the state of pine plantations is critical. The data obtained exceed the criterion for the appointment of measures by 2.6 times, which confirms the need for protective measures.

In the event that no measures were taken, it was assumed that the outbreaks would further spread to adjacent plantations in the territory of the forestry, reduce their biological stability, worsen their sanitary condition, which could lead to the death of artificially created pine crops, a decrease and loss of the target function of the forest.

5. Damage from damage to plantings by the stellate weaver sawfly

The purpose of carrying out measures to localize and eliminate foci is to reduce the number of weaver sawflies, to prevent the decline and loss of the target function of the forest.

Protective measures are assigned when the economic losses as a result of damage to the needles by insects exceed the cost of the protection work being carried out.

To determine the feasibility of the planned protection of the forest in the center of mass reproduction of the star weaver sawfly, an economic assessment of the consequences of defoliation of plantations in these existing centers was carried out according to the “Methods for monitoring forest pests and diseases. Directory. Tom Sh. Moscow 2004.

The total damage from the life of the star sawfly weaver in the forest fund on the territory of the Archedinsky forest area includes:

An economic assessment of damage as a result of drying out of plantations and loss of growth.

Estimation of losses from the decrease in the absorption and recreational properties of the forest.

The total area of ​​foci of the stellate sawfly-weaver according to the data of the Archedinsky forestry is1217,3 ha. Require aerial processing - 696.5 ha.

The economic assessment of damage as a result of the drying of plantings and loss of growth was carried out according to the formula (5):

M 1 = Un[R( t 1 ) - R X( t 1 )] (5)

where;

Un - the proportion of planting drying out;

R( t 1 ) – cost of growing forest;

R X( t 1 ) - the cost of a dried forest;

t 1 - the age of the plantation at the time of the outbreak of mass reproduction.

M 1 = 0,35* = 362253 rubles.

Initial and calculated data are presented in Table 5.1.

Table 5.1.– Forecast of the forthcoming drying out of plantations and loss of growth

Threat for 2016

X (t) C

U O

µ β

CH

P rs, %

0,65

0,75

0,35

1,17

1,27

The cost of a growing forest was determined by the formula (6):
(6)

where:

V- actual stock of timber at felling age, m 3 /ha;

m– cost m 3 wood, rub.;

T– felling age, years;

t 1 – age of the plantation at the time of assessment, years;

ais the discount rate.

rub.

The cost of a dried forest was determined by the formula (7):

R x(t 1 ) = (1-0.006*S)V aboutm about(7)

where:

S– area on which forest drying is expected, thousand ha;

V about– timber stock per 1 ha agedt 1 ;

m about– foam board 1 m 3 wood agedt 1 .

R x( t 1 ) = ( 1-0.006 * 0.696) * 211 * 156 \u003d 32771 rubles

Table 5.2.– Economic assessment of damage as a result of drying out of plantations

V

m, rub.

t1

R(t1)

V o

m o, rub .

R x (t 1 )

Un

M 1 (rub)

228

209,25

101

0,06

1427979

520,8

211

156,46

32909

0,23

320866

Losses as a result of growth losses were determined by formula (7):

*S=7953 rub. (7)

where,

L is a coefficient depending on the breed and pest;

X – degree of damage to the assimilation apparatus, %;

At n – proportion of dead trees;

f(T) – increase in the cost of the plantation stomp payment per year before the felling of the main use;

t 1 is the age of the stand at the time of the outbreak;

T – age of the main felling;

a – discount rate;

S- the area under processing.

Initial and calculated data are given in Table 5.3.

Table 5.3. – Economic assessment of damage from loss of growth

L

X

At n

f(T)

t 1

T

a

M 2(rub)

1,27

92

0,35

209,25

42

101

0,06

5749

Estimation of losses from the decrease in the absorption and recreational properties of the forest. According to the forestry, economic damage from a decrease in the absorption and recreational properties of the forest, from damagestar sawfly weaver in 2016 would be:

M 3 \u003d 696.5 * 0.35 * 1000 * 1000 * 0.01 \u003d 2437750 rubles,

Thus, the total losses from pest activity would be equal to the sum of losses for each of the individual forest target functions.

K=362253+5749+2437750 = 2805752 rubles.

The criterion for the expediency of the fight against needle-and leaf-eating insects is determined by the relation, as K = M 1 + M 2 + M 3 > Zb

K \u003d 2805752 rubles. >668441,5 rub.

Table 5.4. – Economicgradeexpediency of struggle (rub.)

M 1

M 2

M 3

ST of the artist

Zb

qty

∑Zb

To

362253

5749

2437750

635904,50

32537

668441,5

2805752

The amount of damage in plantations where the foci of the star sawfly weaver is 4.2 times higher than the costs of taking measures to localize and eliminate these foci, which justified the need for protective measures.

The unsatisfactory condition of the plantations, the damage of past years and the threat of crops being nibbled by the stellate weaver sawfly, an ecological and economic indicator of the feasibility of control measures, confirmed the need for measures to localize and eliminate the foci of the stellate weaver sawfly.

6. Terms of treatment of the focus

Processing start date is important condition providing a high level of effectiveness of measures to localize and eliminate foci.

According to the observational data, the phenological terms of the development of the stellate weaver sawfly in the conditions of the pine forests of the Archedinsky forestry are presented in Table 6.1. The optimal time to start processing is the period of intensive feeding of the larvae of the stellate weaver sawfly, which falls on the third decade of May and the first decade of June.

Table 6.1. – Calendar of phenological observations of the development of the stellate weaver sawfly on the territory of the Archedinsky forestry

Beginning of larval hatching

from eggs

Mass appearance of larvae

Mass hatching of larvae

from eggs

Mass feeding of larvae

Mass feeding of larvae

first ages

Therefore, the processing of plantings was scheduled for the period from May 25 to May 30, 2016, depending on weather conditions.

It is necessary to carry out processing in an early and short time. This will ensure maximum mortality of the larvae of the stellate weaver sawfly and protection of the stand from damage.

conclusions

When analyzing the ecological and biological characteristics of the studied pest species, the degree of damage in its foci, the reaction of Scotch pine to damage, the following conclusions were made:

The centers of mass reproduction occur in high-density pine plantations of predominantly artificial origin at the age of 12-40 years.

The star weaver sawfly is able to form outbreaks of mass reproduction and to a large extent damage pine plantations over large areas.

Outbreaks of mass reproduction are protracted and often last 9-10 years or more.

On the territory of the Archedinsky forestry, pest foci are formed mainly in artificial plantations of pine.

The star sawfly-weaver is able to have a noticeable negative impact on the state of pine plantations.

In 2015, a severe degree of damage was observed in the outbreak of the Archedinsky district forestry.

Crown defoliation leads to a decrease in growth and a general physiological weakening of plantations, a decrease and loss of the target function of the forest.

Further defoliation, taking into account the threat of 100% overeating in 2016, threatened them with weakening and drying out, as a result of which significant environmental and economic damage would be caused.

Over the past three years, there has been an increase in the number of stellate weaver sawfly.

The amount of damage in plantations, where there are foci of the stellate sawfly, is 4.2 times higher than the costs of carrying out measures to localize and eliminate these foci.

Aerial treatment of the outbreak is planned for an area of ​​696.5 hectares.

Processing of plantations is recommended during the period of mass feeding of larvae from May 25 to May 30, 2016, depending on weather conditions.

The beginning of the treatments at a later date entails an increase in the consumption of the drug, an increase in the cost of work and, most importantly, a decrease in the effectiveness of these treatments.

CONCLUSION

After analyzing the environmental and biological features development of the star sawfly-weaver in pine crops Archedinsky forestry, the reaction of Scotch pine to damage by this type of pest, the development of the outbreak, we made a short-term forecast about the possibility of an increase in the number of the pest during the growing season of 2016 and the threat of 100% overeating of plantations. Forest protection measures in the foci of the sawfly are appointed in the event of a total overeating of crowns by 50% or more. Therefore, in 2016, we have scheduled measures to localize and eliminate the center of mass reproduction on an area of ​​696.5 hectares by air.

LIST OF USED SOURCES

Gninenko Yu. I. Peculiarities of population dynamics of the star sawfly weaver / Yu. I. Gninenko // Ecology. - 1996. – № 4. - S. 310-311.

Lonshchakov S. S. Report on the forest pathological survey of the forests of the Novo-Shulbinsk, Belagach and Semipalatinsk forestries of the Semipalatinsk forestry department: report of the V / O "Lesproekt", 1948.

Kolomiets N. G. Star sawfly-weaver / N. G. Kolomiets. - Novosibirsk: Nauka, 1967. – 135 p.

Fedoryak V. E. Star weaver / V. E. Fedoryak. - Alma-Ata: Kainar, 1970. – 60 s.

Gninenko Yu.I. Star sawfly-weaver in Northern Kazakhstan / Yu.I Gninenko // Agroforestry in Kazakhstan. - Alma-Ata: Kainar, 1983. - S. 133-137.

Ilyinsky A.I. Supervision, accounting and forecast of mass reproductions of needle- and leaf-eating insects in the forests of the USSR / A.I. Ilyinsky I. and V. Tropin. - Moscow " Forest Industry", 1965. – 312 p.

Diseases and pests in the forests of Russia. Directory. Volume 3. Monitoring methods, pests and forest diseases. Moscow, Rosleskhoz. 2004. – 200 s.

Guidelines for the supervision, accounting and forecasting of needle-leaf-eating insects in the European part of the RSFSR. Ministry of Forestry of the RSFSR. Moscow, 1988. - 84p.

Guidelines for the containment and eradication of outbreaks of pests. Annex 4 to the order of Rosleskhoz dated December 29, 2007 No. 523.

Guidelines for planning, organizing and conducting forest pathological surveys. Annex 3 to the order of Rosleskhoz dated
29.12.2007 №523.

To date, the southern region of Nikolaevshchina, in particular the Ochakovsky district and Kherson region, suffer from sawflies - weavers, this family of hymenoptera insects whose larvae are very voracious and damage young shoots of pine trees this and last year. At the moment in Ukraine, three types of weaver sawfly multiply and harm significantly: Pine star sawfly weaver, pear sawfly weaver and bone-bearing sawfly weaver.

Pine star sawfly weaver damages Scots pine and is now eating our forest belts.

Description. Female 11-16 mm, male 10-13 mm. The body is flattened dorsoventrally, black with a variable yellowish-white pattern. In the male, the bottom of the head is entirely yellowish-white, the top is black with separate yellow spots, more noticeable in the female. The chest is black with a variable pattern of yellowish-white spots. Legs reddish, tibiae yellowish. The abdomen is broadly blackened along the middle, rufous along the edges, reddish-yellow below. The egg is shuttle-shaped (in profile), yellowish-white, 2.5-3.2 mm. The larva is cylindrical, 18-26 mm long, with three pairs of black thoracic legs, no ventral legs, and three-segmented cerci at the end of the abdomen. The color is olive green with four brownish longitudinal stripes. Pupa free, yellowish-white, shiny, 12-16 mm.

Lifestyle. Diapausing aeonymph larvae and partly pronymphs overwinter in earthen cradles in the upper soil layer at a depth of up to 10 cm, rarely 40–60 cm. in 20-year-olds - within a radius of 40-50 cm, in ripe and overmature pine forests - within a radius of up to 1 m. Generation is usually one or three years old. Sometimes the diapause of eonymphs extends up to 4-7 years. Eonymphs of individuals with a one-year generation in autumn, approximately three weeks after leaving the soil, turn into pronymphs (with a pigmented "pupa" eye). In the spring, overwintered eonymphs of previous years, of which current year adults emerge, also turn into pronymphs. In April - May, pronymphs molt and turn into pupae. The development of the pupa, depending on the temperature conditions, lasts from 6 to 24 days (on average, 11-12 days).

Adults emerge in May-June. The beginning of the mass summer usually coincides with the beginning of the dusting of male inflorescences of Scots pine and the flowering of apple and lilac. In Polissya, imago occurs in the period from the second decade of May to mid-June, occasionally extending until mid-July. Eggs are laid singly, rarely 2-4 (rarely 8) on last year's pine needles, usually in the well-lit upper part of the crown of 10-40-year-old trees of natural and artificial pine stands. Fertilized eggs develop into females, while unfertilized eggs develop into males. Female fecundity fluctuates different years and is 15-50 eggs. After 8-28 days, larvae hatch, which go through 5-6 instars in their development. The larvae live one at a time in cobweb tubes - covers woven among the needles on the May pine shoots. The tubules of this species, unlike the tubules formed by some other coniferous weavers, are not covered with excrement and needle stubs. At first, the larvae eat young needles, and later descend down the branches and feed on last year's needles. At V-VI instars, the larvae leave their caps and live freely among the needles braided with cobwebs. The duration of development of larvae before leaving the soil is from 14 to 30 days.

Mass reproduction of the weaver occurs periodically, every 10-15 years. In Ukraine, centers of mass reproduction were noted in the forest-steppe forests of Kharkov and Voroshilovgrad regions.

Control measures. Plowing in autumn and early spring of cutting areas in the centers of mass reproduction of the pest; attracting insectivorous birds by hanging artificial nests; resettlement of the red forest ant; the use of insecticides (Nurel-D, Calypso, Decis Profi, etc.) at the beginning of hatching of larvae.

Pear sawfly weaver damages pear, apple, hawthorn, bird cherry, sweet cherry, apricot, peach, pomegranate, cotoneaster, quince, medlar.

Description. Imago 11-14 mm, head black, antennae 18-24-segmented with yellow I-II and blackish-rufous following segments. The thorax is black with light yellow wing-caps, often with yellow spots. Abdomen rufous or brownish-yellow, rarely entirely black with whitish lateral spots. Legs yellow, more or less blackened at base. The wings are transparent with a brownish band under the pterostigma. Larva up to 20 mm, yellow or orange with a shiny black head and two black scutes on the first thoracic segment. Abdominal legs are absent. At the end of the abdomen are long three-segmented cerci.

Lifestyle. Diapausing larvae-eonymphs hibernate in the soil at a depth of up to 20 cm, in earthen "cradles". They pupate in late April-May. The pupal stage is 15-20 days. In May - early June sawflies emerge from the soil. After fertilization, the females lay their eggs in groups of 40-60 leaves below. Eggs in the clutch are placed in a tile-like manner and overlap one another. The larvae hatch in 10-12 days, form web nests resembling apple moth nests, and live in them in groups. The larvae of the first age skeletonize the leaves, the older ones completely eat them. The feeding period lasts 30-35 days, after which the larvae go to winter in the soil. The larvae are very voracious, one nest is enough for complete defoliation of a 4-6-year-old pear tree. In a part of the population, wintering eonymphs do not pupate and remain in a state of diapause for the second wintering.

Control measures. When larvae are found, spraying trees with organophosphate insecticides: chlorophos, rogor, karbofos, or others.

Bonefruit Sawfly Weaver

Description. Imago 7-10 mm, body black with white spots on the head (behind the eyes, on the crown of the head, in the female also in the middle of the palisade). Antennae setiform, long, 20-21-segmented, black. The thorax is black, only the margin and lateral angles of the pronotum; in the female, the spots on the lobes of the mesoscutum and scutellum are also often white. Legs reddish-yellow, blackened in the basal half. The wings are transparent. The abdomen is black with white spots on the sides, sometimes with white stripes along the posterior margin of the tergites. The egg is elongated oval, yellowish white. The head is black-brown. Larva up to 15 mm, green with four dark scutes on the first thoracic segment and a dark dorsal stripe. There are no ventral legs. Last abdominal segment has long three-segmented podanal cerci.

Lifestyle. Diapausing eonymph larvae overwinter in soil cradles. In April they pupate. Imago after hatching one more - two days remain in the soil. Summer from late April to early June. Usually its beginning coincides with the phenophase of the deployment of leaf buds of cherries. Immediately after mating, females glue fertilized eggs with secretions of special adnexal glands mainly on the youngest leaves at the tops of the shoots and only partially on the lower leaves in a chain or in groups, usually 7-17, less often up to 65-70 pieces. Additional power imago is not observed. The period of laying eggs by one female lasts 3-4 days, and often their entire supply (50-74 pieces) is deposited on one leaf. Sometimes different females lay eggs on the same leaf, as a result of which there are up to 120 eggs on one leaf. Embryonic development lasts 9-14 days. The larvae fasten the young leaves with cobwebs and skeletonize them. They live in groups of different sizes depending on the number of eggs laid on the leaf. Older larvae cobweb most of the leaves on the branch, forming a large web nest filled with excrement and leaf stubs. Leaves are eaten from the edges or perforated. The feeding period lasts 24-35 days, depending on meteorological conditions. In the nest, the larvae can quickly move in different directions along the web, and under unfavorable meteorological conditions they hide among the remains of leaves inside the nest.

At the end of June - beginning of July, the larvae stop feeding and descend along the cobwebs along the branches and trunk, or simply fall to the ground, where they make an oval cell - a "cradle" at a depth of 10-25 cm and hibernate in it. In a dry spring, eonymphs do not pupate and remain in a state of diapause for wintering. Thus, there is an optional two-year generation.

Weaver sawflies are a large family of Hymenoptera insects.

Outwardly similar to true sawflies.

Distributed throughout the Eurasian continent and North America.

Relating to pests coniferous trees.

Description of insects

All representatives of this family reach a length of 10 to 15 mm. They have flagellate antennae, three pairs of legs with a tooth located on each of them. On the head are large movable crescent-shaped mandibles and parallel sutures associated with the antennal grooves.

The wings are transparent, membranous, with a sparse network of veins, the anterior ones are longer than the posterior ones. Laid flat on the back horizontally. Paws are walking, there are spurs on the shins. The larvae have well-developed pectoral tarsi and no ventral legs at all; the antennae consist of 7 or 8 segments.

Varieties

Star sawfly weaver

The head and breast are black with yellow and white spots. The abdomen is yellow-brown with black dots in the middle. Wings are transparent, veined. The female is larger than the male, it reaches a length of 12-16 mm, and the male is only 10-12 mm.

The larva grows up to 25 mm, has six black pectoral legs. Longitudinal brown stripes are located on the olive-green body. The pupa is shiny, yellowish-white in color, located freely in the cocoon.

Red-headed Weaver Sawfly

It has a wide, flattened body in the abdomen. The wings are dark, almost black, and have specific veins that are characteristic of all sawflies. In the female, the entire head is painted bright red, in males, only the front part - the “face”. The back is yellow.

The larvae have strongly developed pectoral tarsi, colored in green color with a gray or yellow tint. Longitudinally along the entire body are brown stripes, across - rows of inconspicuous spots. The head is yellow-brown, the legs are greenish-yellow.

Single sawfly weaver

The entire body (head, chest and abdomen) is black and yellow. They reach 13–18 mm in length. The wings are transparent, light yellow in color, with a sinuous venation.

The larva, or caterpillar, is dirty green in color with a gray tint, has three pairs of pectoral and one pair of false legs on the last segment of the body. The head is light green-brown. The larva grows up to 25 mm in length.

Yellowmouth weaver sawfly

The belly is yellow-brown, the breast and head are black. The mouthparts are bright yellow, as is the first segment of the antennae. Wings transparent, characteristic venation. The larva is yellow-orange, the head is black. Reaches a length of 18-22 mm.

reproduction

The larvae settle down for wintering, going underground to a depth of 15–30 cm. In the second half of April or early May, they molt and pupate. Adults appear in 10–13 days. Within 3-4 weeks, the flight and mating of adults last.

The female lays eggs on needles, placing them in groups of 2-5 pieces. The average fecundity of one adult female is 40–60 eggs. Egg development lasts about two weeks, after which larvae emerge.

Sawflies have partial parthenogenetic reproduction, therefore, only males emerge from unfertilized eggs, and females from fertilized ones.

Young larvae arrange a common nest of cobwebs, wrapping around branches with needles. Older larvae weave individual cobweb cases for themselves. The development of the larva takes about a month, it goes through six instars. Having reached the last stage of development, the caterpillar begins to feed openly, no longer hiding in a cobweb cover.

In the middle of summer, the larvae descend, arranging a kind of cradle in the ground - a hole with compacted walls. About half of the larvae turn into pronymphs in early autumn. This form will become an imago in the spring. The other half become eonymphs and enter a state of diapause for up to three years.

In September, future eyes are outlined in pronymphs - black dots appear on the head, which are absent in eonymphs.

Maliciousness

All of the above varieties of weaver sawflies are pests of coniferous trees - pines, spruces.

Especially often weaver sawflies attack young trees.

With mass attacks of insects, both the tops and entire trees can dry out. The greatest harm is caused by larvae that eat needles in large quantities.

Trees weakened by sawflies are very susceptible to attack by bark beetles and other stem pests.

Ways to fight

mechanical method

Hands collect spider nests of larvae and destroy them by burning. This method is possible only in small areas of personal use.

Agrotechnical measures

Also used in personal household plots. To reduce the number of pests, digging the soil under the trees in autumn is effective.

biological methods

Predatory spiders attack adults. Eonymphs suffer from predatory ground beetles, hedgehogs, shrews, wood mice. The eggs can be eaten by other insect larvae and the sun.

In addition, insecticides of biological origin are used. The use of Actofit, Aktarofit, Vermicide, Agravertin is effective.

Chemicals

Chemical preparations are applied during the appearance of larvae. Systemic agents effective against hymenoptera are suitable for the destruction of sawflies. These include:

• Actellik is a drug from the group of organic phosphorus compounds. It has a very wide range of effects, affecting the nervous system of insects.
• Bankol is a nicotinoid used against chewing and sucking pests. Neurotoxin action provides paralysis and subsequent death of sawflies.
• Biotlin is a systemic remedy containing. This is a new generation substance from the chlornicotinyl group. Blocks the transmission of nerve impulses of pests.
• Decis pro is a synthetic pyrethroid available in the form of water-soluble granules that are easy to dose. As a result of its influence, irreversible depression of the nervous system occurs.
• Intavir is a pyrethroid containing cypermethrin. It works well against a large complex of pests, including weaver sawflies. Paralyzes leaf-eating insects and their larvae.
• Calypso is a drug from the chlornicotinyl series with a systemic effect. Differs in low toxicity for the environment, very weak resistance.