First record of entomopathogenic fungus Entomophaga aulicae in the populations of browntail moth in Bosnia and Herzegovina

Abstract

Browntail moth, is a well-known pest of broadleaf forests of Bosnia and Herzegovina. Although it is extremely polyphagous, it prefers to consume the leaves of various species of oaks. Browntail moth occurs periodically in high numbers (outbreak). Entomopathogenic fungus Entomophaga aulicae (Reichardt and Bail) Humber (Zygomycotina: Entomophtorales, Entomophtoraceae) is widespread Holarctic species, with many host insects from order Lepidoptera, where are some of the most economically harmful, outbreaking species of forest defoliators. In sessile oak forests of Eastern Bosnia and Herzegovina, the population density of browntail moth was determined by using route measurement during the growing season in the period 2015-2016. Browntail moth newly litters (40) were collected in four oak stands located in the region of Foča, Višegrad and Rogatica (PE Forests of the Republic of Srpska, Forest Estates Maglić, Panos and Sjemeć). In the litters, there were an average of 3,1 of dead old caterpillars and 4.7 pupae.The evaluation of E. aulicae infections was recorded as positive when hyphal bodies, primary conidia, or resting spores were detected on the surface of cadavers and puparia or in their tissues. The species identification was based on the size, shape and structural characteristics of different life forms of the fungus. By the microscopical studies of the causes of the mortality of the browntail moth larvae and pupae, the presence of hyphal bodies, primary conidia and resting spores of the E. aulicae were confirmed in them. The dimension of the resting spores (n=257) are 32.4 - 48.5 µm, a.v. 44.1 µm, primary conidia (n=54) 26.7-38.6 x 21.0-43.1 µm, a.v. 34.1-29.3 µm. Hyphal bodies were not measured. As entomopathogenic fungus on two development stages of the host, larvae and pupae, presented results indicate that E. aulicae is a promising microbial control agent.

Stuck in the Caterpillars’ Web: A Half-Century of Biocontrol Research and Application on Gregarious Lepidopteran Pests in Europe

“…Bulgarian researchers dealt with microsporidian infections, predominantly with Nosema sp. [99,100] and Entomophaga aulicae (Reichardt) [101]. The latter entomopathogenic fungus was, after its initial report for Serbia in 2015, assessed as a significant control agent by Tabaković-Tošić and Milosavljević [102], who also investigated E. aulicae presence in Bosnia and Herzegovina two years later [103].…”