Abstract
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.
Highlights
Gypsy moth (Lymantria dispar L., Lepidoptera: Erebidae) is the most important defoliator in the deciduous forests of Europe, Asia and North Africa
This study presents the results of an applied biological control programme by E. maimaiga release to suppress the gypsy moth outbreaks in four locations in Bulgaria
After the introduction in Bulgaria, the fungus E. maimaiga has constantly expanded its range in the East European countries
Summary
Gypsy moth (Lymantria dispar L., Lepidoptera: Erebidae) is the most important defoliator in the deciduous forests of Europe, Asia and North Africa. Soon after its accidental introduction into North America in 1869, the gypsy moth started its spread as an alien invasive species, causing severe defoliation and shade trees due to the absence of natural enemies (Hajek, 2007). In Bulgaria, during severe outbreaks, L. dispar defoliates 110-370 thousand ha of forest deciduous stands (Georgiev et al, 2013). In 1989 the pathogen was identified in gypsy moth epizootic in seven north-eastern states (Andreadis, Weseloh, 1990). E. maimaiga has expanded its range by natural spread and artificial introductions in new localities of L. dispar (Solter, Hajek, 2009). Inoculative releases of E. maimaiga accelerate the spread of the pathogen and help to reduce the impact of initial and future outbreaks of the pest (Hajek et al, 2021)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
