Testing of soil distribution, viability, and infectivity of azygospores of the entomopathogenic fungus Entomophaga maimaiga

Abstract

Entomophaga maimaiga is one of the best-known gypsy moth pathogens with increasing importance in the biological control aimed at reducing the population of this defoliator. The territory of the Republic of Serbia is a very favorable gypsy moth habitat, and the problems caused by its larvae during the periods of outbreaks are so great that they can lead to forest defoliation and forest health deterioration. In the Republic of Serbia, E. maimaiga was first recorded in 2011 (as a new species in the microflora of Serbia) during the gypsy moth outbreak (2009-2014), which was the last to date. In 2011, numerous dead caterpillars were found on and around trees in oak and beech stands of the Belgrade and Valjevo regions in Serbia. Subsequent laboratory analyses revealed that they contained azygospores and conidia of this fungus. The assisted introduction of E. maimaiga was carried out in Compartments 28 and 30 of the FMU Avala on Mt. Avala in 2011. It led to an epizootic in the following year and stopped the outbreak of the gypsy moth in the area. Since it has been seven years since the outbreak, we tested the viability and infectivity of E. maimaiga azygospores obtained from the soil samples from Avala Mountain where its assisted introduction was carried out. We used larvae from the laboratory gypsy moth population and applied the bioassay method. The results show that azygospores are present in the given soil samples, they are viable and their infectivity is conserved. It can be concluded that in the case of an outbreak of gypsy moth populations in the future, they will exhibit their entomopathogenic effect