Isolation and molecular identification of entomopathogenic fungi from the Western flower thrips [Frankliniella occidentalis (Pergande)], and evaluation of their efficacy against the pest

Abstract

The Western flower thrips (WFT), Frankliniella occidentaliss (Pergande) (Thysanoptera: Thripidae), is the main pest of many vegetables and ornamental plants in greenhouses in Antalya province (southwestern part of Turkey). The objectives of this study were: (i) to isolate indigenous Entomopathogenic fungi (EPFs) from naturally infected individuals of WFT in the coastal area of Antalya, where greenhouse cultivation is intensively done, (ii) to identify EPF isolates using DNA sequencing, and (iii) to assess the effectiveness of the isolates against various developmental stages [larvae (1st and 2nd instars), pupa and adult (only females)] of WFT under laboratory conditions. In pathogenicity assays, all isolates were tested at three different conidial concentrations (1 × 10⁵, 1 × 10⁶ and 1 × 10⁷ conidia/ml), using the spray method. Two Beauveria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes) isolates (M48 and M49) and Isaria fumosorosea Wise formerly [formerly known as Paecilomyces fumosoroseus (Wise) (Ascomycota: Hypocreales)] isolate (M50) were the most pathogenic, causing 100% mortality of WFT larvae within 7–10 days at the highest concentration (1 × 10⁷ conidia/ml). These three isolates also caused a mortality of more than 85% in the pupae of WFT. The Lecanicillium psalliotae (Treschew) Zare & W. Gams (Ascomycota: Hypocreales) isolate (DOA3) was the most virulent against adult females of WFT, causing 100% morality at the highest concentration 10 days after treatment. The current study’s findings suggested that certain EPF extracted from WFT cadavers may provide an important foundation for the creation of bioproducts, as well as a possible alternative technique for regulating WFT.