Isolation, characterization and virulence of entomopathogenic fungi from Gryllotalpa gryllotalpa (Orthoptera: Gryllotalpidae)

Abstract

Mole crickets are significant pests of turf, vegetable and some tree seedlings worldwide, and it is costly to control them. In this study, we obtained 15 fungal isolates from Gryllotalpa gryllotalpa L. (Orthoptera: Gryllotalpidae) and compared the efficacy of these isolates against this pest with the aim of identifying their biocontrol potential. The fungal isolates were identified based on their morphological and molecular characteristics, using ITS, EF1-alpha, Bloc, RPB1, RPB2 and beta-Tubulin gene sequencing. Consequently, the isolates were identified as Beauveria bassiana (Balsamo) Vuillemin (Gg-1), Clonostachys sp. (Gg-2, Gg-3, Gg-5, Gg-6, Gg-8 and Gg-13), Bionectria sp. (Gg-4), Metarhizium anisopliae (Metschnikoff) Sorokin (Gg-7, Gg-12 and Gg-14), Clonostachys rogersoniana (Schroers) (Gg-9 and Gg-15), Myriodontium sp. (Gg-10) and Myriodontium keratinophilum (Samson and Polon.) (Gg-11). These isolates caused mortalities ranging from 0 to 87 %, with the most virulent fungus being M. anisopliae Gg-12, which caused 87 % mortality within 15 days post inoculation using a conidial concentration of 1 x 10(7) conidia ml(-1). Concentration-response test was conducted to determine the LC50 value of M. anisopliae Gg-12, and it was calculated as 1.069 x 10(6) conidia ml(-1). As a result, M. anisopliae Gg-12 can be further investigated in terms of controlling mole crickets.