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The role of natural regulators of the number of brown-tail moth and their significance in the dynamics of the pest population has been studied. In the course of a statistical analysis of the influence of factors of the biotic environment on older caterpillars, an inverse relationship was established between their numbers and survival in a given age range. This is important for the subsequent application of the obtained data in the practice of plant protection.

The biological peculiarities of brown-tail moth, a dangerous pest of many tree and garden plantings, were studiedin order to develop a rapid method for obtaining sufficientlyfast and reliable accounting and forecasting data. A comparative description of the existing methods of accounting ofbrown-tail moth in forest plantations and in garden ones hasbeen carried out. It has been established that the accounting methods adopted in production are devoid of statisticaljustification and data on the size and number of accountingunits. It is shown that the most informative indicator for obtaining data on the population of stands is the developmentof phytophage at the caterpillar phase in winter nests. Masscounts of winter nests with a simultaneous estimate of thenumber of caterpillars in them and the degree of nibblingof plantations made it possible to identify the relationshipbetween these values. Tables for quick determination of therequired sample size with three levels of accuracy are developed. A table establishing the number of pest larvae depending on the size of wintering nests has been developed. Amodel that allows predicting the degree of expected damageto plantings by a pest has been obtained.

В лесных насаждениях Пензенской области, часто возникают вспышки массового размножения многих опасных насекомых. Среди листогрызущих фитофагов вызывающих ослабление и усыхание растений наибольшее значение имеет златогузка. Однако в области изучения особенностей появления, развития и распространения златогузки существует немало проблем. Следуя данным, на сегодняшний день является малоисследованным вопрос о формировании очагов вредителя. В частности, отсутствуют данные о конкретных лесорастительных условиях наиболее соответствующих развитию вредителя. Исследования показали, что наилучшими условиями для развития златогузки отличались дубравы состоящие из дуба порослевого происхождения рано распускающейся формы. В породном составе дуб составлял от 40 до 100%. Примесь других пород была представлена березой, осиной, кленом, липой. Возраст насаждений варьировал от 15 до 65 лет. Полнота древостоя колебалась от 0,4 до 0,7. Тип леса Д2, Д3, С3 – дубравы низкоствольные I–VI бонитетов 1 яруса. Согласно данным, наибольшее число гнезд златогузки было выявлено в дубравах чистых по запасу, в возрасте 50 лет и полнотой 0,4. По числу гусениц, содержащихся в гнезде, наблюдалась сходная тенденция. Анализ выживаемости гусениц после перезимовки показал, что высокий уровень ее был отмечен лишь в чистых по составу дубравах-92,1%. Многие гнезда расклевывались птицами, что устанавливалось по характерным их повреждениям. Смертность гусениц происходила также от заболеваний и неустановленных факторов. Было установлено, что популяция златогузки концентрировалась, главным образом, в верней части кроны деревьев, менее в средней. В нижней части кроны гусеницы практически отсутствовали. Выявлено что, наибольшая численность вредителя была на дубе черешчатом ранней формы. Заселенность златогузкой отмечалась также на осине, березе, липе и клене, где концентрация златогузки была приурочена на южной части деревьев., In the forest stands of the Penza region, there are often outbreaks of mass reproduction of many dangerous insects. Among the leaf-eating phytophagans, which cause the plants to weaken and shrink, the brown-tail moth is of the greatest importance. However, there are many problems in studying the characteristics of the appearance, development, and distribution of the brown-tail moth. Following the data, today the question of forming the pest outbreaks is under-investigated. In particular, there are no data on specific forest conditions most relevant to the development of the pest. Studies have shown that the best conditions for the development of the brown-tail moth were oak trees, consisting of early setting scrub forms of oak. In the species composition, oak ranged from 40 to 100%. Impurity of other breeds was represented by birch, aspen, maple, and linden. The age of plantations ranged from 15 to 65 years. The fullness of the stand varied from 0.4 to 0.7. Forest type D2, D3, C3 – low-growth oak forests of I–VI bonitet, the 1st synfolium. According to the data, the largest number of brown-tail moth nests was found in pure stock oak forests, 50 years of age and with a fullness of 0.4. According to the number of caterpillars contained in a nest, the similar trend was observed. The analysis of the larvae survival rate after wintering showed that its high level was noted only in purely oak forests of 92.1%. Many nests were pecked by birds; it was determined by their characteristic damage. Caterpillar mortality was also caused by diseases and unidentified factors. It was found that the population of browntail moth was concentrated mainly in the upper part of the tree crown, less in the middle. Caterpillars were practically absent in the lower part of the crown. It was revealed that the greatest number of the pest was on early-leafed oak. The population of brown-tail moth was also noted on aspen, birch, linden and maple, where its concentration wisp was confined to the southern part of the trees., №11 (2019)

Summary The browntail moth (Euproctis chrysorrhoea L.) fairly frequently completely defoliates oak trees in the part of the country South of the river Waal and in the “Achterhoek”, and buck thorn in the dunes region along the coast. In the “Veluwe” defoliation has been observed as an exception only. In the Northern provinces the species in question never caused important damage. In appears, therefore, that the North limit of the area in which outbreaks of the browntail moth occur, runs from West to East through the Netherlands. From time to time the limit moves to the North, and back again after a few years. An hypothesis was advanced according to which the increase of the damage and the movement of the limit of the outbreak region to the north would be caused by changes in the quality of the food, resulting from changes in weather conditions. In order to find out whether there is any likelihood of the nature of the food affecting the population dynamics of the brown tail moth in our country, two series of experiments were carried out. a. Field experiments with colonies placed in oak, hawthorn, apple and birch by the experimentor. It appeared that there were considerable differences in the development of the caterpillars on the different plant species and in the different localities. b. Laboratory experiments in which oak, hawthorn and apple leaves were fed to the caterpillars showed that they thrived best on hawthorn, less well on apple and least on oak. It is, therefore, concluded that an influence of the nature of the food on the population dynamics of the brown tail moth may be decisive. Further experiments are in progress.

Gusjenice mnogih leptira predstavljaju značajne štetnike različitih voćnih vrsta. Jedan od opasnijih štetnika je Zlatokraj (Euproctis chrysorrhoea L.) koji u godinama masovne pojave izaziva golobrst voćaka. Na području općine Prozor-Rama (Federacija BiH) u 2013. godini zabilježena su velika oštećenja u nasadima voćaka zbog napada gusjenica Zlatokraja. Osim fiziološkog slabljenja voćaka evidentirana su i odumiranja mladih stabala u nasadima šljiva kao izravna posljedica napada spomenutog štetnika. U slučaju normalne i povišene brojnosti štetnik se može suzbijati dok u godinama prenamnoženja Zlatokraj postaje veliki problem. Da bi se suzbila pojava tog štetnika, primjenjuju se mehaničko-fizičke, kemijske i biološke mjere., The caterpillars of many butterflies represent significant pests of various kinds of fruit. One of the more dangerous pests is Brown-tail moth (Euproctis chrysorrhoea L.) that in the years of mass phenomena causes defoliation of fruit trees. In the municipality Prozor-Rama (Federation of BiH) in 2013, great damages to plantations of fruit trees were observed from attacks by catepillars of Brown-tail moth. Not only physiological weakening, but also dying of young trees in plum plantation were recorded as a direct result of the attack by mentioned pest. In the case of normal and elevated number of pests, it’s possible to suppresse them, but in case of overpropagation it becomes a big problem. In order to combat it, the mechanical-physical, chemical and biological measures are available.

In laboratory conditions, urticating hairs from the pine processionary caterpillar (Thaumetopoea pityocampa S.) and from the brown tail moth (Euproctis chrysorrhoea L.) are detectable in the air using an apparatus designed for the capture of airborne microorganisms and pollen research studies. The hairs produced by the caterpillars of these two species are distributed either via air currents or moths (only forEuproctis). Daily cycles of hair emission were observed and were in relation with locomotion and feeding activities of the caterpillars and with flying and reproductive activities of moths.

A description is given of both naturally occurring and experimentaly produced brown-tail moth caterpillar dermatitis. Epicutaneous test reactions were studied in a group of 45 persons, utilizing different setae preparations obtained from Euproctis chrysorrhoea L. About 70% of the individuals developed marked reactions upon contact with untreated nettling hairs. The early skin lesions were as a rule erythematous and wheal-like in character (urticarial), gradually becoming more infiltrated and developing into erythematous papules or vesicles. Treatment of the nettling hairs either by heating or saline extraction resulted in a partial loss only of their skin irritating properties; heat treatment being slightly more effective in this respect. Intracutaneous tests with a sline extract of nettling hairs elicited positive skin reactions in all individuals tested. Biochemical analysis of the crude extract revealed the presence of a potent esterolytic enzyme. Apart from their skin irritating action, the nettling hairs were found capable to induce the formation of spherocytes when mixed in vitro with human erythrocytes. The relevance of this phenomenon is discussed. On the basis of our findings and those of other it is suggested that the action of the nettling hairs upon the human skin is dependent both on a toxic and mechanical traumatic principle.

The transmission of a nuclear polyhedrosis virus was investigated within a single generation of the Brown-tail moth, Euproctis chrysorrhoea (L.). Larvae infected with a lethal dose of virus were introduced onto bramble bushes naturally infested with the host, in separate studies in the spring and autumn. The course of infection was followed and clearly showed the development of a secondary infection peak in the spring. The presence of a secondary peak in the autumn was also suggested. These peaks are considered to have resulted from the passage of the virus from the primary infected larvae into further larvae. Virus dispersal was more widespread in the spring than in the autumn reflecting differences in larval dispersal. Zusammenfassung Uher das Auftreten sekundarer Infektionszahlen nach Anwendung eines Kernpolyeder-Virus gegen eine Population des Goldafters, Euproctis chrysorrhoea (L.) (Lep., Lymantriidae) Es wurde die Ubertragung eines nuklearen Polyeder-Virus in einer Generation des Goldafters, Euproctis chrysorrhoea (L.) untersucht. Die Raupen wurden mit einer letalen Dosis des Virus infiziert und dann in Brombeerstrauchern freigelassen, die naturlicherweise mit Goldafter-Raupen besetzt waren. Die Untersuchung wurde zweimal, im Fruhling und Herbst, durchgefuhrt. Der Verlauf der Infektion wurde verfolgt, und die Infektionskurve zeigte klar die Entwicklung einer sekundaren Spitze im Fruhjahr. Moglicherweise existierte auch noch eine sekundare Spitze im Herbst. Diese Spitzen stammen vermutlich aus einer Ubertragung des Virus von den primar infizierten Raupen auf weitere Raupen. Der Virus verbreitete sich im Fruhjahr weiter als im Herbst, vermutlich wegen unterschiedlicher Wanderlust der Raupen.

Two different aspects related to the dermatitis caused by the so-called nettling hairs of the larva of the brown-tail moth, Euproctis chrysorrhoea L., are documented. The first part describes the sequence of histopathologic changes associated with the inflammatory process in the human skin induced by epicutaneous application untreated (UT-N) and heat treated (HT-N) nettling hairs. The penetration of untreated and heat treated nettling hairs into the epidermis is evident from their presence in 12 out of 29 UT-N lesions and 5 out of 10 HT-N lesions respectively. The introduction of nettling hairs into the skin leads to damage and bulla formation of the surface epithelium and early inflammatory signs consisting of edematous changes of the dermis and pervascular infiltration of neutrophils, eosinophils and mononuclear leucocytes. After few hours the intensity of the dermal infiltrate has increased and spongiotic changes appear. After 48--72 h the perivascular infiltrate is mainly composed of mononuclear cells, while along with increased spongiosis the damaged surface epithelium may show repair. The traumatic changes of the surface epithelium in HT-N lesions appear less prominent in comparison with the UT-N lesions. The second part describes the findings obtained by scanning electron microscopy of the nettling hairs. Evidence is brought forward to support the view that the offending setae may be looked upon as tapering, hollow microcapillaries which are open at both ends. The present findings are consistent with the idea that the nettling hairs may serve as microneedles from which irritant substances may be liberated when penetrating into the skin, and that the resulting inflammatory reactions are attributable to combined mechanical and toxic effects.

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1. Further survey of the japanese brown tail moth (Euproctis pseudoconspersa STRAND) was made concerning the larval moulting of the first generation. From the results of this survey together with the first report, it was found that the larvae had five-seven moultings but some of them might have eight moultings as they did in the second generation.2. The total life-cycle from larva to adult took 53-61 days at 25°C., and 75% R.H. This period was one month or 12-20 days shorter than that of the first or second generation in the natural environment.3. The number of eggs containing in the abdomen of 60 female moths was counted, one female had 373.5 eggs on an average and 454 in maximum which was much larger than that of laid eggs.The number of the residual eggs in the abdomen of 10 females after laying eggs was 81.3 on an average, 292 in maximum, and 58 in minimum.4. The number of eggs containing in eggmasses collected in the field was as follows:5. In Japan (Kanaya), they repeated two generations a year, the larvae had five-eight moultings, and the male moths had two seasonal color forms, one was black and the other yellow as female. The former appeared in the first generation, and the latter in the second.In Formosa (Taipei), they had five generations a year, the larvae had usually five moultings, the black moths appeared in summer' the yellow in winter, and the intermediate in April.6. Two species of Hymenopterous egg parasites were found in Japan, one was Telenomvs sp. (Scelionidae) and the other Trichogramma dendrolimi MATSUMURA. The percent parasitization by the former species was 38.4% in the first generation, and 8.7% in the second in 1953, while that of the latter was 0.3% in the first and 0.5% in the second respectively.The former species was one of the most important natural enemy on Evproctis pseudoconspersa whose host was recorded as only one. The latter was not so effective enemy on Evproctis pseudoconspersa, however, seventeen other hosts were found and was a very effective parasite on the tea tortrix (Adoxophyes privatana WALKER, Homona coffearia NIETNER) and Phrixolepia serieea BUTLER (Coehlidionidae).

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The paper pertains to recent investigations in Europe of the Gipsy Moth and Brown-tail moth and their natural enemies. Mention is made of the previous work which resulted in the introduction of 36 species of Tachinid and Hymenopterous parasites and 10 species of beneficial Coleoptera. Of the 46 species named, 15 have actually been established.

This paper deals with the results of the introduction of the parasites of the gipsy moth, Porthetria dispar , and brown-tail moth, Euproctis chrysorrhoea , during the past 20 years, and indicates that this work has been enormously beneficial. A number of the parasites have, apparently, reached their maximum and during the past two years a sharp decrease in parasitism has been noticed. In several sections ether infested area this has been followed by rapid increase in the abundance of the gipsy moth and just at present the work is passing through a critical stage, with no reliable information as to whether the gipsy moth or its enemies will gain permanent control. An enormous amount of scientific data have been secured and further efforts are being made to introduce other parasites that attack the gipsy moth.

This study attempts to evaluate the possible pathogenic role of phospholipase A2 and of proteolytic c.q. esterolytic enzyme(s) recently shown to be associated with the skin irritating nettling hairs ofEuproctis chrysorrhoea caterpillars.

Electron microscopical studies were made of the arrangement patterns of nucleocapsids within the envelope of the nuclear-polyhedrosis virus with naturally infected larvae of the brown tail moth, Euproctis similis. Number of nucleocapsids observed in an envelope in their cross sections ranged from 1 to 39, and the frequencies at 4, 7, 10, 12, 14, 16, 19, 21, and 24 nucleocapsids were significantly higher than the others, suggesting that these numbers of nucleocapsids were more commonly involved in an envelope. Arrangement patterns represented by these particular numbers of nucleocapsids seemed to be regulated by some unknown mechanisms. However, it was speculated that polygonal shapes such as triangle, lozenge, trapezium, pentagon, or hexagon of cross-sectioned envelopes would have resulted from a well-regulated mode of assemblage of the component nucleocapsids as described. More than three nucleocapsids are more stable when they are made into a bundle, in which lateral surfaces of the nucleocapsids are circumscribing each other and fitting in at angles of about 60° as depicted in Figure 24. The central row is always composed of the largest number of nucleocapsids and two rows consisting of the one less number of nucleocapsids are disposed on the both sides of the central row, thenceforth a certain number of rows involving nucleocapsids that decrease by one in due order being situated bilaterally, finally forming the polygonal-shaped outline. Therefore, the total number of nucleocapsids increases in proportion to the numbers of nucleocapsids in the central row and to the numbers of rows.

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A review is given of the recurrent outbreaks of the tentcaterpillar, Malacosoma neustria L., affecting the elm trees in the city of Amsterdam in the period 1930—1957. An outbreak of the brown tail moth, Euproctis chrysorrhoea L., in 1935—1936 is also mentioned and some occasional loss of foliage through the caterpillars of the vapourer moth, Orgyia antiqua L. Large fluctuations in the size of the Malacosoma populations were found. After some years in which the damage was negligeable, the increase always started in the N.W. part of the centre of the city. In the following years the outbreaks moved to adjacent parts of the centre and finally sometimes even to more eccentric parts (see Fig. 6—9). However, the occurrence of really harmful numbers of tentcaterpillars was mostly restricted to the centre of the town. The merits of the control measures which were carried out with derris/talcum powder spread by motordusters are discussed. The insecticide was thought to be the only sufficiently harmless for its use in the centre of a city. Some cases of defoliation and other inconveniences caused by the presence of crowds of caterpillars could apparently be reduced by the control measures. In several instances, however, the efficacy of the method remained doubtful. The urgency is stressed of further studies of the bionomics of Malacosoma under local conditions and some suggestions are made for a better organization of the measures applied.

It is well known that certain lepidopterous larvae possess urticating hairs which are the cause of a more or less severe and painful irritation when they come in contact with the human skin. In this country, the one which has attracted the most general attention on this account is the larva of the imported brown-tail moth, Euproctis chrysorrhoea. A great many cases of poisoning have been attributed to this species, and one death has been reported as the result of severe internal poisoning caused by inhaling the hairs. There has been much discussion among scientists as to whether the effect of these hairs is purely mechanical or whether they are actually poisonous, but on the other hand, singularly little definite study has been made of the morphology of the hairs and their underlying structures. It was for this reason that the subject of this paper was suggested by Dr. W. A. Riley and to him the writer is greatly indebted for much kindly criticism and many helpful suggestions. In 1894 Packard described the poisonous spines of Lagoa crispata, stating that the spines themselves were secreted by certain large trichogen cells lying under the rest of the hypodermis and connected with the spines through pore canals in the cuticle. In addition to these cells there were other smaller ones lying in different places above and below the hypodermis, and even in the pore canal itself, which he called "poison nuclei," and which he claims secrete the poison. Ingenitsky (1897) studied several different forms, especially Ochneria monacha Linn., and he clearly demonstrated that there are two cells connected with each hair and that the smaller of the two is the trichogen cell, which, after secreting the hair, decreases in size, and that the large cell is the actively secreting poison gland. Aside from the fact that Ingenitsky carefully traced the development of the two cells through all stages of the larva, this view would seem to be the reasonable one, because one would naturally expect to find that the actively secreting cell was larger than one that had already stopped its action. This latter is the same view as that expressed by Holmgren (1895). He also found that the poison hairs were connected with two cells, one somewhat larger than the other, one of which secreted the hair and the other the poison.

Fumigation of brown-tail moth, Euproctis chrysorrhoea nests, in mid-winter show that brown-tail moth larvae were killed when fumigated at 50o F., and in many cases when the temperatures were as low as 39o F. European corn borer larvae, pyrasuta nubilalis , taken from a storeroom at a temperature of 40o to 45o F., and fumigated in a temperature of 65o to 70o F., were not killed. Borers frequently counted as dead from two to fourteen days after fumigation were found to recover and even complete their transformations. The experiments, with few exceptions, represented two hour fumigation periods, much better results being obtained when the time was extended to from six to ten hours.

While so much is being written of the dermatitis caused by the brown tail moth and other agents, a narration of the following case may be of slight interest: The patient was Mrs. R., 59, married, the mother of four children. While in attendance for an attack which proved to be appendicitis, I noticed a suffusion of the face and made inquiry thereto. She gave a history of having suffered from a most obstinate dermatitis for three years, with occasional exacerbations and remissions. Itching and burning were intolerable and at times a severe conjunctivitis was also present. She had consulted various physicians, together with one or two specialists, and had persistently followed the usual course of treatment with salines, ointments, and alteratives, until finally some one had introduced her to the term "dyscrasia," which she had seized avidiously, becoming resigned to her fate. Accompanying her husband on his annual trips

Dermatitis as a result of contact with the brown tail moth (Euproctis chrysorrhea Linn) was first observed in the United States by White1in 1901. The rash was noted a few minutes to several hours after exposure to the cocoon, caterpillar or adult moth and either remained localized at the site of contact or became generalized. The most frequently occurring lesion2was a discrete erythematous maculopapule occurring singly or in groups, which in the cases of severe disease coalesced to form urticarial wheals. Steele and Sawyer3described wheals with vesicular or shallow necrotic centers. Pruritus was a constant complaint and was described as mild to intense; constitutional symptoms were not noted. The duration of the eruption varied from five to seven days, although in rare instances several weeks elapsed before resolution. While it was recognized early that the dermatitis was provoked by the nettling hairs functioning as

A review is given of the recurrent outbreaks of the tentcaterpillar, Malacosoma neustria L., affecting the elm trees in the city of Amsterdam in the period 1930—1957. An outbreak of the brown tail moth, Euproctis chrysorrhoea L., in 1935—1936 is also mentioned and some occasional loss of foliage through the caterpillars of the vapourer moth, Orgyia antiqua L. Large fluctuations in the size of the Malacosoma populations were found. After some years in which the damage was negligeable, the increase always started in the N.W. part of the centre of the city. In the following years the outbreaks moved to adjacent parts of the centre and finally sometimes even to more eccentric parts (see Fig. 6—9). However, the occurrence of really harmful numbers of tentcaterpillars was mostly restricted to the centre of the town. The merits of the control measures which were carried out with derris/talcum powder spread by motordusters are discussed. The insecticide was thought to be the only sufficiently harmless for its use in the centre of a city. Some cases of defoliation and other inconveniences caused by the presence of crowds of caterpillars could apparently be reduced by the control measures. In several instances, however, the efficacy of the method remained doubtful. The urgency is stressed of further studies of the bionomics of Malacosoma under local conditions and some suggestions are made for a better organization of the measures applied.

THE BROWN-TAIL MOTH The brown-tail moth or Euproctis chrysorrhaea was one of the first insects destructive to fruit-trees to be described by entomologists. The moth is a native of Europe and is common in all parts, except the extreme north. It is said that it first invaded this country in 1892, infesting a small territory in the vicinity of Somerville and Cambridge, Mass., the method of introduction being the importation of some roses from Holland by a Somerville florist.1It was not until 1897, however, that any scientific investigations were made concerning the insect in this country. At this date the Massachusetts State Board of Agriculture pursued a series of investigations to discover the insect causing the destruction of vegetation in and about the suburbs of Boston and proved the brown-tail moth