scholarly journals Biological control of gypsy moth (Lymantria dispar) by the entomopathogenic fungus Entomophaga maimaiga in Bulgaria in 2021

2021 ◽  
Vol 22 (3) ◽  
pp. 17-27
Author(s):  
Georgi Georgiev ◽  
Plamen Mirchev ◽  
Margarita Georgieva ◽  
Mihail Kechev ◽  
Sevdalin Belilov ◽  
...  
Keyword(s):  
Biological Control ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Entomopathogenic Fungus ◽  
Control Programme ◽  
Egg Mass ◽  
Moth Population ◽  
Entomophaga Maimaiga ◽  
Forest Enterprises ◽  
Gipsy Moth

In 2021, biological control programme against gipsy moth (Lymantria dispar) populations was carried out by introduction of the entomopathogenic fungus Entomophaga maimaiga on the territory of four State Forest Enterprises: Municipal Enterprise (ME) ‘Management of Municipal Forests, Agriculture and Forestry’, Nessebar; State Game Enterprises (SGE) Nessebar and Balchik; State Forestry (SF) Vidin. The pathogen was introduced during the period 15-26.03.2021 in 34 localities - five in ME Nessebar, eight in SGE Nessebar, ten in SGE Balchik and eleven in SF Vidin. The average number of gypsy moth population density in the locations of introduction was relatively high, ranging between 0.4-15.9 egg mass/tree in the area of ​​SGE Balchik and 11.9-65.0 egg mass/tree in the area of ​​ME Nessebar. The average mortality of young gypsy moth caterpillars (first-third instar) due to E. maimaiga varied between 2.6% (SGE Balchik) and 13.0% (SF Vidin), and of caterpillars in later fourth-sixth instar - between 20.7% (SF Vidin) and 52.4% (ME Nessebar). The overall mortality of the gipsy moth caterpillars due to E. maimaiga was lowest in the region of SGE Balchik (26.1%), followed by SF Vidin (33.7%), SGE Nessebar (48.5%) and ME Nessebar (55.9%). As a result of the introduction, gipsy moth severe outbreaks in the region of Nessebar was significantly suppressed. The high number of E. maimaiga resting spores persists in the surface layers of the soil in the other two areas (Vidin and Balchik) has the potential to suppress L. dispar attacks in next years.

Augmenting Nucleopolyhedrovirus Load in Gypsy Moth (Lepidoptera: Lymantriidae) Populations with Egg Mass Treatments

2003 ◽  
Vol 38 (2) ◽  
pp. 300-313 ◽  
Author(s):  
R. E. Webb ◽  
G. B. White ◽  
K. W. Thorpe
Keyword(s):  
Gypsy Moth ◽  
Early Treatment ◽  
Adult Emergence ◽  
Field Studies ◽  
Host Population ◽  
Egg Mass ◽  
Moth Population ◽  
Egg Masses ◽  
Entomophaga Maimaiga ◽  
Virus Dose

Previous observations show that gypsy moth, Lymantria dispar L., mortality induced by the fungus Entomophaga maimaiga Humber, Shimazu & Soper is quickly manifested as host population density increases. However, the gypsy moth nucleopolyhedrovirus (LdMNPV) lags behind the rebounding gypsy moth population. In this study, egg masses were contaminated with virus to successfully augment LdMNPV in gypsy moth populations in Virginia. Laboratory bioassays determined the approximate LdMNPV dose to apply to egg masses with and without the addition of the virus enhancer Blankophor BBH to the spray mixture. The highest dose of virus (5.3 × 105 PIBs/mL) tested without Blankophor BBH gave 82.3% mortality. Mortality for this virus dose increased to 91.8% when 1% Blankophor BBH was added. Field studies established that application of virus at an earlier date (04 April) was as efficacious as an application made at a later date (12 April); this study also included a further assessment of the addition of Blankophor BBH to the spray mixture. While application of LdMNPV + Blankophor BBH resulted in faster kill, levels of kill were similar (88.0% for early treatment and 78.8% for later treatment for virus applied alone versus 87.8% for early treatment and 89.1% for later treatment for virus + Blankophor BBH). However, a higher than expected number of cadavers in the LdMNPV + Blankophor BBH treatments had few or no polyhedral inclusion bodies (PIBs). Finally, virus infection resulting from the application of LdMNPV to pupae in June 1998 was compared with infection levels seen after the application of virus to egg masses in April 1999. The April 1999 treatment to egg masses clearly resulted in a higher kill of emerging larvae (=79.3% mortality) compared to the June 1998 treatment to female pupae (with virus incorporated into the egg masses laid by females after adult emergence) (=13.7% mortality). The virus was recovered season-long from larvae collected from populations in the treated plots (but not from control plots), indicating within season spread.

scholarly journals Occurrence of gypsy moth (Lymantria dispar L.) in the Slovak Republic and its outbreaks during 1945–2020

2021 ◽  
Vol 67 (2) ◽  
pp. 55-71
Author(s):  
Milan Zúbrik ◽  
Andrej Kunca ◽  
Ján Kulfan ◽  
Slavomír Rell ◽  
Christo Nikolov ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Slovak Republic ◽  
Tree Plantations ◽  
Moth Population ◽  
The Past ◽  
Entomophaga Maimaiga ◽  
History Of

Abstract The gypsy moth is one of the most serious pests in forests and fruit tree plantations over prevailing parts of the Northern Hemisphere. This work is based on a literature review, and presents history of gypsy moth Lymantria dispar L., observed in Slovak forests within the period 1945–2020. The life cycle, hosts, natural enemies, population dynamics of pests, impact of outbreaks on forests and different management methods used in the past are discussed. Since 1945, there were nine gypsy moth outbreaks in Slovakia. Between 1945 and 2020, a total of 155,034 ha of deciduous forests were touched with varying intensity, representing an average annual damage of 2,040 ha. The strongest outbreak culminated in 2004. Totally 51,479 ha were attacked in the period of 2000–2008. We have found outbreak periods that repeat with frequency of 7.8 ±2.2 years and the average outbreak phase lasts 3.1 ±1.1 years. The period between two subsequent outbreaks seems to be more or less constant and duration of the outbreak phase seems to be gradually shortened during the study period. Several factors influencing the gypsy moth population dynamics in Slovakia are discussed. The role of biological control by using entomopathogenic fungus Entomophaga maimaiga is described.

scholarly journals Effectiveness of Diflubenzuron and Bacillus thuringiensis Against Gypsy Moth Populations

1997 ◽  
Vol 14 (3) ◽  
pp. 135-140 ◽  
Author(s):  
Kevin W. Thorpe ◽  
Richard L. Ridgway ◽  
Ralph E. Webb
Keyword(s):  
Bacillus Thuringiensis ◽  
Population Density ◽  
Gypsy Moth ◽  
Mass Density ◽  
Larval Mortality ◽  
Larval Density ◽  
Egg Mass ◽  
Percent Reduction ◽  
Moth Population ◽  
Oak Trees

Abstract Aerial applications of Bacillus thuringiensis Berliner subsp. kurstaki (74.1 billion international units/ha per application; single and double applications), diflubenzuron [69 g (ai)/ha], and no treatment were evaluated. Treatment effects were estimated from frass collections, defoliation, counts of pupae under burlap, and egg-mass counts. Estimates of larval density in the canopy 20 days after treatment ranged from 318.3 to 55.5 larvae per m² in the control- and diflubenzuron-treated plots, respectively. Larval density was reduced in all treatments, and was lowest in the plots treated with diflubenzuron and two applications of B. thuringiensis. Population density rapidly declined in the control plots, and by June 20, when larvae were predominantly in the fifth and sixth instars, no significant differences in larval density were detected among the treatments. Significantly less defoliation occurred to oak trees in the treated plots, but no differences were detected among the spray treatments. Counts of pupae under burlap, postseason egg-mass counts, and percent reduction in egg-mass density did not differ significantly among treatments or versus controls. These results suggest that diflubenzuron and double B. thuringiensis treatments caused higher levels of larval mortality than occurred with a single B. thuringiensis application, but that with a naturally declining gypsy moth population the final levels of damage were the same under all treatments. North. J. Appl. 14(3):135-140.

Isolation and characterization of Entomophaga maimaiga sp. nov., a fungal pathogen of gypsy moth, Lymantria dispar, from Japan

1988 ◽  
Vol 51 (3) ◽  
pp. 229-241 ◽  
Author(s):  
Richard S. Soper ◽  
Mitsuaki Shimazu ◽  
Richard A. Humber ◽  
Mark E. Ramos ◽  
Ann E. Hajek
Keyword(s):  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Fungal Pathogen ◽  
Isolation And Characterization ◽  
Entomophaga Maimaiga

Quantitative Analysis of a Pathogen-Induced Premature Collapse of a “Leading Edge” Gypsy Moth (Lepidoptera: Lymantriidae) Population in Virginia

1999 ◽  
Vol 34 (1) ◽  
pp. 84-100 ◽  
Author(s):  
R. E. Webb ◽  
G. B. White ◽  
K. W. Thorpe ◽  
S. E. Talley
Keyword(s):  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Nuclear Polyhedrosis Virus ◽  
Leading Edge ◽  
Late Season ◽  
Early Appearance ◽  
Entomophaga Maimaiga ◽  
Resting Spores ◽  
Nuclear Polyhedrosis ◽  
Second Wave

The population dynamics of a “leading edge” (= at the edge of the expanding gypsy moth invasion) gypsy moth, Lymantria dispar (L.), population was monitored for 3 years (1995–97), with emphasis on the interactions of the gypsy moth nuclear polyhedrosis virus (LdNPV) and the fungus Entomophaga maimaiga Humber, Shimazu, & Soper. Gypsy moth populations in the woodlots varied from very sparse to high (potentially defoliating) levels. LdNPV was strongly density dependent, being confirmed only from the higher populated woodlots. In contrast, the fungus was similarly active in both sparse and highly-populated woodlots. In 1995, the fungal epizootic developed late in the season, with most larvae succumbing during stadia 5–6 and producing mainly resting spores (azygospores). Estimated mortality due to fungus averaged 68% in high-density plots and 85% in low-density plots. LdNPV mortality occurred in a two-wave epizootic, although second-wave LdNPV mortality was undoubtedly reduced because of the reduction of late-season larvae due to fungus activity. Estimated mortality due to LdNPV averaged 14% in highly-populated plots and 1% in low-population plots. In 1996, high levels of fungal-induced mortality occurred earlier in the gypsy moth season than in the previous year. Most gypsy moth larvae in 1996 died in a mid-season wave of fungal-induced mortality, with necropsied cadavers containing only conidia. This resulted in relatively few larvae surviving to late instars. At this time, a second wave of fungus-induced mortality occurred, with over half of the necropsied cadavers containing resting spores. The depletion of the gypsy moth populations by the fungus in 1995 resulted in a greatly reduced first wave of LdNPV in all plots in 1996, and perhaps due to the early appearance of the fungus in 1996, LdNPV was nearly absent from late-season larvae collected from all plots. In 1997, gypsy moth populations were uniformly low, and no dead larvae were found in any of the plots.

Distribution of late instar Lymantria dispar cadavers killed by Entomophaga maimaiga on trunks of several tree species in southwestern Japan

2007 ◽  
Vol 85 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Shota Jikumaru ◽  
Toshikazu Sano
Keyword(s):  
Biological Control ◽  
Lymantria Dispar ◽  
Tree Species ◽  
Quercus Serrata ◽  
Broadleaf Forest ◽  
Entomophaga Maimaiga ◽  
Quercus Glauca ◽  
Resting Spores ◽  
Late Instar ◽  
Clethra Barbinervis

Attachment of late-instar Lymantria dispar L. (Lepidoptera: Lymantriidae) cadavers killed by Entomophaga maimaiga Humber, Shimazu et Soper (Zygomycetes: Entomophthorales) on trunks of five dominant tree species was determined in a broadleaf forest in southwestern Japan. The highest numbers of cadavers were found attached to the trunk of Pasania glabra (Thunb.) Oerst., while there were moderate numbers of cadavers on the trunks of Quercus glauca Thunb. and Quercus serrata Thunb. and no cadavers were found attached to trunks of Ilex pedunculosa Miq. and Clethra barbinervis Sieb. et Zucc.. All examined cadavers contained E. maimaiga resting spores. The differences in cadaver attachment among tree species may influence density of E. maimaiga resting spores around tree bases, which act as reservoirs for fungal survival during unfavorable periods or over numerous years. Our results provide important information as to where to collect E. maimaiga resting spores for biological control of L. dispar, especially in forests containing many tree species.

Successful Completion of an International Project of the Department of Natural Sciences at New Bulgarian University

2021 ◽  
Vol 6 ◽  
pp. 82-86
Author(s):  
Daniela Pilarska ◽  
Christa Schafellner ◽  
Gernot Hoch ◽  
Margarita Georgieva ◽  
Georgi Georgiev ◽  
...  
Keyword(s):  
Lymantria Dispar ◽  
Natural Enemy ◽  
Entomopathogenic Fungus ◽  
Natural Sciences ◽  
International Project ◽  
Research Fund ◽  
Successful Completion ◽  
The West ◽  
Entomophaga Maimaiga

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.

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