Isolation and characterization of entomopathogenic fungi from the Eastern Black Sea region and determination of their virulence

In this study, in order to find more effective and safe biocontrol agents against some pest species which have wide spread in the Eastern Black Sea Region, a total of 301 soil samples were collected and 62 entomopathogenic fungi were isolated by Galleria bait method. Separetely, two fungi were isolated from Thaumetopoea pityocampa (Schiff.) (the pine processionary moth) and Rhynchites baccus (L.) (the leafroller weevil beetle) insect samples. Obtained isolates were characterized by using morphological and molecular techniques in detail. Based on taxonomical studies, the isolates were identified as Metarhizium anisopliae var. anisopliae, Metarhizium sp., Beauveria bassiana, Beauveria cf. bassiana, Isaria fumosorosea and Evlachovaea sp. M. anisopliae var. anisopliae was isolated from 34 sites and was the most frequent and abundant fungus recovered. In addition, genetic diversity of 13 B. bassiana and 33 M. anisopliae var. anisopliae strains was determined by using the Amplified Fragment Length Polymorphism (AFLP) analysis. A significant genetic diversity was found within B. bassiana isolates and this diversity was found to be associated with geographical location (p<0,05). Although there is also a significant genetic diversity within M. anisopliae var. anisopliae isolates, this diversity is not associated with habitat type and geographical location (p>0,05). After performing of screening test of the isolates against Tenebrio molitor (mealworm) larvae, nine isolates that have high insecticidal activity were tested against Melolontha melolontha (the common cockchafer) and Dendroctonus micans (the European spruce bark beetle). Based on pathogeniticy tests, Evlachovaea sp. KTU-36 produced the highest insecticidal activity with 86,6% against M. melolontha within 15 days and B. cf. bassiana KTU-53 caused the 100% mortality against larvae and adulst of D. micans within 6 days. Separately, LC50 value of B. cf. bassiana KTU-53 against larvae and adults of D. micans was calculated as 1,77 × 104 and 2,65 × 104 conidia ml-1, respectively.