Isolation and identification of entomopathogenic fungi from western flower thrips, Frankliniella occidentalis (Pergande) (thysanoptera: thripidae), and screening of their efficacy against the pest

Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), which is the major pest of many vegetable and ornamental plants in greenhouse growing in Antalya, can both directly damage plants by sucking plant sap and indirectly damage as the vector of some important plant viruses. Entomopathogenic fungi (EPF) are one of the most widely used microbial control agents in pest control worldwide. Local isolates of EPF in geographic areas where pests are found have important advantages in control. In this study, F. occidentalis individuals infected or suspected of being infected with EPF were collected from different locations representing the region in the best way in Kemer, Kumluca, Finike, Kaş, Konyaaltı, Manavgat and Aksu counties of Antalya Province where agricultural activities are carried out intensively. Among the collected thrips samples were examined under a stereo-microscope in the laboratory, and those which were dead, alive and showing disease symptoms were determined. EPF-infected individuals were isolated in SDA medium. As a result of the isolations made from the samples brought; 31 different isolates belonging to the genera Akanthomyces, Alternaria, Aspergillus, Beauveria, Cladosporium, Fusarium, Isaria, Lecanicillium and Sporothrix were obtained. In order to determine the 5 most effective fungal isolates, all fungal isolates were screened for their pathogenicity against F. occidentalis. Pathogenicity assays were carried out in a climate chamber with a temperature of 25 ± 1℃ and a relative humidity of 70 ± 5%. At a conidial concentration of 1 x 107 conidia/ml, 2 isolates of Beauveria bassiana (M48 and M49), 1 isolate of Isaria fumosorosea (M50), 1 isolate of Akanthomyces muscarius (DOA1) and 1 isolate of Lecanicillium psalliotae (DOA3) were determined to have high pathogenic activity with a mortality rate of ≥75% against F. occidentalis. The remaining 26 isolates showed no pathogenicity in the study conducted against F. occidentalis. The isolates (M48, M49, M50, DOA1 and DOA3), which had been determined as promising pathogens in preliminary tests, were assayed at three different spore suspansions (1 x 105, 1 x 106 and 1 x 107 conidioa/ml) for their pathogenicity against different biological stages (larvae, pupa and adult females) of F. occidentalis in a climate chamber with a temperature of 25 ± 1℃ and a relative humidity of 70 ± 5%. During the study, the 5 most virulent fungal isolates were identified morphologically, and the species identification of all isolates was confirmed by using molecular methods. As a result, it has been suggested that the isolates, M48, M49, M50, DOA1 and DOA3 can be used effectively in biological control of F. occidentalis due to having high mortality rates against different life stages of pest.