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This paper presents the results of the study of the population levels of the gypsy moth in the forests of National Park Đerdap, over the period 1996-2014. The characteristics of three outbreaks of the gradogenic character were studied. Since these are forest ecosystems of the natural protected areas in which the special rules and measures aimed at...
The population dynamics and impacts of non-native species often change following their initial establishment, with impacts either increasing or decreasing over time. The reasons why the abundance of an invading species may change are varied but often reflect changes in the way in which populations interact with resident communities. Here we analyze...
The Asian fungal entomopathogen Entomophaga maimaiga was first introduced in Bulgaria for biological control of gypsy moth, Lymantria dispar, in 1999 and the first epizootics in gypsy moth populations were observed in 2005. Six introductions of E. maimaiga in oak forests with heavy L. dispar infestations were conducted from 2008 to 2011 in differen...
Biological control of gypsy moth ( Lymantria dispar ) was carried out in 2021 in the field protective forest belts at the territory of the State Hunting Enterprise Balchik by introducing the entomopathogenic fungus Entomophaga maimaiga (Entomophthorales: Entomophthoraceae). In the same year a mortality rate of 26.1% of the pest population was regis...
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... This is very unfortunate considering that this group has much narrower host ranges than Hypocreales fungi, and most importantly and different to the latter, is their capacity to produce epizootics and, therefore, being very good at regulating natural population of their pests (Pell et al., 2001;Eilenberg and Pell, 2007). Surprisingly, few efforts have been made at using entomophthoralean fungi in inundative biocontrol strategies (Milner et al., 1982;Hajek and Webb, 1999;Pilarska et al., 2007;Hajek and Delalibera, 2010), probably because their conidia are very fragile, sensitive to different conditions such as temperature and humidity, and difficult to mass produce (Pell et al., 2001;Eilenberg and Pell, 2007). ...
Conidiobolus lunulus is a recently described entomophthoralean species isolated from leaf-cutter ants. This fungus discharges not only primary but also secondary conidia and microconidia of different shapes. Because nothing was known about the biology of the fungus, and its interactions with hosts, we first evaluated if its pathogenicity against leaf-cutter ants changes with the fungal age (time grown in vitro), and if it is related to the conidial structures produced. Afterwards, we tested its virulence at three combinations of temperature and relative humidity. In addition, we noted all visible causes of death by recovering different microorganisms from the dead, non-sterilized, ants to evaluate C. lunulus virulence when pathogens carried naturally by the ants were present. Finally, we used the conditions that lead to the highest mortality to evaluate fungal virulence to other host species, including non-leaf-cutter ants. Results indicated that C. lunulus was pathogenic from a culture age of 1 to 5 days, with a peak at 2-days-old, from which we registered median lethal times of 1-2 days and 85% of the cadavers with fungal conidiation. Our results suggest that primary conidia and moon-shaped microconidia were infective. Evaluations of mortality using 2-days-old cultures on several leaf-cutter ant colonies showed 1) significantly faster mortality of C. lunulus inoculated ants in comparison to controls, 2) significantly greater and faster mortality at 23.7 °C than at 21.2 °C, 3) significantly higher and faster mortality at 88% than at 57% RH, and 4) a significant reduction of other pathogens in C. lunulus inoculated ants in comparison to controls. C. lunulus was highly specific to leaf-cutter ants, as hardly any increase in mortality was observed on inoculated ants, and no conidia were recorded on cadavers of the other three non-leaf-cutter ant species tested. Our results highlight that C. lunulus is a very promising biological control agent against leaf-cutter ants.
... In the period 2000-2004 the prevalence of E. maimaiga in local populations of L. dispar ranged from 6.1% (2000) to 15.9% (2004). However, the fungus persisted in the introduction site and in 2005, massive epizootics caused by this fungus were recorded in State Forestry Haskovo and State Forestry Kirkovo ( Pilarska et al., 2007). In 2012 fungal epizootics were reported from the regions of State Forestry Haskovo and Harmanli with larval mortality of 100%. ...
During the period 1990-2017, a survey of the entomopathogens and parasitoids of several pest insects was conducted, including the lepidopterans Lymantria dispar, Euproctis chrysorrhoea, Leucoma salicis, Malacosoma neustria, Orthosia cerasi, Aporia crataegi, Operophtera brumata, Eilema complana, Tortix viridana, Archips xylosteana, Paranthrene tabaniformis, Gypsonoma aceriana, Thaumetopoea pityocampa, T. solitaria, Phyllocnistis unipunctella, the coleopterans Saperda populnea, Ips typographus, I. acuminatus, I. sexdentatus, Pityogenes chalcographus, Dryocoetes autographus, Hylurgops palliatus, Phyllobius sp. and the hymenopterans Diprion pini, Neodiprion sertifer, Gilpinia sp. and Tremex fuscicornis. As a result of these studies 5 viruses, 1 protozoan species, 7 microsporidian species, 5 species of entomopathogenic fungi and 46 parasitoid species have been documented in 27 host insects collected in the region of the Forest Protection Station Plovdiv. The first successful introduction in Bulgaria of the entomopathogenic fungus Entomophaga maimaiga in populations of L. dispar was conducted in 1999 in the region of the Forest Protection Station at Plovdiv (in the village of Gorni Domlyan, Karlovо Forestry) and 7 subsequent introductions were later performed in the region of the station. As a result, L. dispar density has been maintained at low levels in that area and only 60 hectares were sprayed with insecticides for L. dispar control in the last 18 years. Another success was the first field release in Europe and Bulgaria of the entomopathogenic fungus Entomophaga aulicae in a healthy population of the brown tail moth, Euproctis chrysorrhoea, in 2016 in the village of Zhenda (Kardzhali Forestry). Investigations in 2017 showed that 19% of E. chrysorrhoea larvae sampled from release sites had died due to infection by E. aulicae.
... E. maimaiga е интродуцирана за първи път в България през 1999 г. с биологичен материал от саЩ (Pilarska et al., 2000). няколко години по-късно са наблюдавани първите епизоотии на гъботворката от патогена на значителни разстояния от местата на интродукциите (Pilarska et al., 2007;georgiev et al., 2010). Чрез нови интродукции и естествено разширение на ареала, E. maimaiga потиска няколко силни каламитета на L. dispar и се разпространява почти повсеместно в страната (georgiev et al., 2012a; 2013). ...
... kurstaki or chemical pesticides like Dimilin. Efforts to improve the existent environment friendly strategies were the reason to study fungal pathogens – their biodiversity (PaPierok et al. 1984, solTer et al. 2000, 2002, Jankevica 2004, Mirchev 2004, Pilarska et al. 2001, 2006 Polovinko et al. 2010; seviM et al. 2010), pathogenicity (er et al. 2007; Polovinko et al. 2010; seviM et al. 2010) and to conduct introduction of the entomophthorous fungus Entomophaga maimaiga Humber, Shimazu & Soper (Pilarska et al. 2000Pilarska et al. , 2007Pilarska et al. , 2010). The aim of the study was to establish naturally occurring fungal pathogens on some lepidopteran forest pests in Bulgaria and to estimate the relative ...
Fungal entomopathogens found in natural populations of 7 lepidopteran forest pests were isolated and identified. Beauveria bassiana was established as a dominating species followed by Fusarium sp. and Aspergillus sp. The pine processionary moth Thaumetopoea pityocampa was the most affected by B. bassiana – 66.7% of the analysed dead larvae of the pest. The occurrence of B. bassiana in Malacosoma neustria, Tortrix viridana and Melitaea didyma is the first record in Bulgaria.
Relative susceptibility of first-second instar Lymantria dispar larvae was estimated to three B. bassiana and one Metarhizium anisopliae isolate and susceptibility of third instars – to seven B. bassiana and one M. anisopliae isolate. The bioassays showed that L. dispar larvae were tolerant to mycoses caused by the tested B. bassiana isolates and M. anisopliae. M. anisopliae isolate caused mycosis to first-second instar larvae with the highest lethal effect 56.67% ± 4.84 and B. bassiana isolates 561Bb and 575Bb to third instar larvae – 47.78% ± 4.06 and 34.44% ± 3.28, respectively, in 17 days period.
... Pest management organizations in South and Central European countries currently use the microbial insecticide Bacillus thuringiensis Berliner subsp. kurstaki (Btk) and more broad spectrum insecticides such as Dimilin® and Mimic® to manage damaging gypsy moth larval populations (Pilarska et al., 2007). In Sardinia, the gypsy moth population has been monitored annually since 1980 in 282 sites, primarily in the major cork, holm (Quercus ilex L.) and pubescent oak (Quercus pubescens Willd.) ...
Gypsy moth (Lymantria dispar L.) larvae were collected in 20 oak stands in Sardinia to evaluate mortality factors. Collected larvae
were reared in the laboratory on artificial diet until they died or pupated. Larval mortality ranged from 17.5 to 100%. Parasitoids
that killed larvae and pupae were identified and the remaining larvae were evaluated for presence of pathogens. Of the five
parasitoids species recorded, the dipteran tachinid Blepharipa pratensis Meigen was the most frequently observed and caused up
to 57.5% mortality. The viral pathogen LdMNPV caused mortality up to 37.5%. We recorded the presence of the fungus Beauveria
bassiana (Balsamo-Crivelli) Vuillemin as well as the microsporidium Nosema portugal Maddox et Vavra, which was previously
identified as Nosema lymantriae Weiser. The fungal entomopathogen Entomophaga maimaiga Humber, Shimazu et Soper
was not collected from the host populations surveyed. We suggest that an inoculative introduction of this pathogen into Sardinia
could potentially reduce the need to control gypsy moth populations with microbial pesticides, which are expensive to apply and
are toxic to many non-target organisms.
... The data from field and laboratory experiments characterize the fungus as a very host specific pathogen of the gypsy moth that is not harmful to non-target organisms (Hajek et al., 1995Hajek et al., , 1996Hajek et al., , 2000). Bulgaria is the first country in Europe where E. maimaiga was successfully introduced and became established (Pilarska et al., 2000Pilarska et al., , 2006Pilarska et al., , 2007 Georgiev et al., 2007). The fungus was imported from the US and introduced on six different occasions to L. dispar populations in the region of State Forestries (SF) Svoge (1996 and 2001), Karlovo (1999), Assenovgrad (2001, Nova Zagora (2008), Popovo (2009) and Gorna Oriahovitsa (2009) (Fig. 1). ...
... However, our results from both sites indicate that E. maimaiga has persisted despite the low density of its host. In 2005, massive mortality of gypsy moth larvae caused by a fungal pathogen occurred at four sites in Bulgaria (SF Haskovo, Kirkovo, Botevgrad and Govezhda) located 30-70 km from our introduction sites in 2000 and 2001 (Georgiev et al., 2007; Pilarska et al., 2007) (Fig. 1). ...
... In 2005, an epizooty caused by E. maimaiga occurred at four different sites in Bulgaria (SF Haskovo, Kirkovo, Botevgrad and Govezhda) located 30-70 km from the introduction sites in 2000 and 2001 Pilarska et al., 2007). In 2008 and 2009 the range of the fungus was expanded by its introduction into three new sites (SF Nova Zagora, SF Popovo and SF Gorna Oryahovitsa). ...
Study of protozoan parasites and pathogens of forest pest insects is a perspective concerning the biological control. The subject of our investigations in this respect were 2 arthropod species which are serious pests in the forests, nurseries, greenhouses, etc.: Lymantria dispar and Oxidus gracillis. Our research on the pathogens of L. dispar started since 1995 in cooperation with European and USA investigators. As a result of our study three protozoan parasites – Vairimorpha disparis, Nosema lymantriae and Endoreticulatus schubergi (Microsporidia) were observed on this pest. In 2000 experimental studies on the introduction of an entomopathogenic fungus Entomophaga maimaiga into L. dispar populations in Bulgaria have started. The results obtained showed that the fungus has been successfully introduced in Bulgaria and practical results are expected in the next years. O. gracilis is a new invasive species for Bulgarian fauna from Far East which lives so far in greenhouses, nurseries, etc. Its wider distribution in the country is expected at our climatic conditions. Three protozoan parasites were recorded on this millipede – Stenophora nematoides, Stenophora robusta and Fonsecaia polymorpha (Apicomplexa: Sporozoa). While S. nematoides and S. robusta showed a high prevalence, F. polymorpha was detected in a few individuals only. Study of protozoan parasites and pathogens of forest pest insects is a perspective concerning the biological control. The subject of our investigations were two arthropod species which are serious pests in the forests, nurseries, greenhouses, etc.: Lymantria dispar Linnaeus (Insecta, Lepidoptera) and Oxidus gracillis (C.L. Koch), (Myriapoda, Diplopoda).
The study examines the results of complex geophysical research of threearchaeological sites located near the southern part of the Black Sea coastline in Bulgaria:Propadnalata Voda, Atiya, and Alepu. The authors discuss the use of complex geophysical methodsin archaeology depending on the objectives of archaeological research, on the one hand, and thelikely properties of the archaeological sites, on the other. As known, the methods of appliedgeophysics involve reverse geophysical problems, which do not have definitive solutions. Toovercome potential ambiguities in this regard, the study demonstrates how the complementary useof different methods makes the interpretation of the final results easier.
The paper presents the results of a successfully completed international project of the Department of Natural Sciences titled “Monitoring and identification of the entomopathogenic fungus Entomophaga maimaiga in Lymantria dispar populations” and funded by the National Research Fund in 2017-2019. Investigating the distribution of E. maimaiga in Austria and Bulgaria in 2018-2019 shows that the pathogen has expanded its range to the west and reached Lower Austria. E. maimaiga has been identified in Bulgaria as well and has become part of the natural enemy complex of L. dispar.
Microsporidia, pathogenic protists related to the Fungi, are considered primary pathogens of many aquatic and terrestrial insects and have important roles in insect population dynamics, managed insect disease, and biological control of insect pests. Hosts are infected when spores are ingested and/or by transmission via eggs. When ingested, spores germinate in a unique fashion: a polar tube that is coiled within the spore rapidly everts and punctures the host midgut cells, injecting the spore contents into the cell cytoplasm. These obligate intracellular pathogens lack mitochondria and Golgi bodies, and evidently extract energy from host cells via direct uptake of ATP. Effects on the host are typically chronic; therefore, the use of microsporidia in biological control programs focuses on inoculative introductions, augmentative release, and conservation biology. This chapter reviews the biology, ecology, pathology, and classification of microsporidia with examples of long-term research efforts to manipulate these pathogens to suppress insect pests.
