Molecular characterisation and efficacy of entomopathogenic fungi against the Green shield bug Palomena prasina (L.) (Hemiptera: Pentatomidae) under laboratory conditions

Green shield bug (GSB) Palomena prasina (L.) causes significant yield and quality losses in hazelnut production of Turkey. Alive and dead adults of GSB were collected from the main hazelnut cultivation areas of Turkey during 2018 and 2019. The entomopathogenic fungi (EPF) were isolated from GSB individuals and identified by DNA sequencing of the internal transcribed spacer of the rRNA. Phylogenetic analysis based on the maximum likelihood method of these sequences with reference sequences retrieved from GenBank revealed that 20 native isolates were Beauveria bassiana (6), B. pseudobassiana (1), Cordyceps confragosa (5), Akanthomyces muscarius (4), Purpureocillium lilacinum (2), Isaria fumosorosea (1), and Bionectria sp. (1). Furthermore, the isolates were tested for their efficacy against GSB adults at 1 x 10(8) spores mL(-1) concentration under laboratory conditions. Registered bio-insecticides were applied at the same concentration to compare the efficacy of the isolates. Beauveria spp. isolates were most effective among the tested isolates with LT50 and LT90 values ranging between 3.65-6.14 and 5.26-8.25 days, respectively. These isolates caused 100% mortality in GSB adults within 6-10 days. The isolates of A. muscarius (TR-OR-1) and P. lilacinum (TR-SM-7) were highly effective and caused 100% mortality 10 and 11 days after the treatment, respectively. These results indicated that some EPF isolates obtained in this study are more promising as an alternative control agent against GSB.