New Approaches to Evaluating the Effectiveness of Entomopathogenic Fungi in Microbiological Plant Protection against the Western Flower Thrips Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae)

Data on virulence of various species of entomopathogenic fungi of the genus Lecanicillium against the thrips Frankliniella occidentalis and the effect of the fungal spores and mycelium on the behavioral responses of the phytophage are presented. A pronounced repellent effect was found for 7 strains: Vl 21 (Lecanicillium muscarium), Vit 117 and Vit 71 (L. attenuatum), 2332 (L. dimorphum), 8057 and F 2 (L. lecanii), and Vl 13 (L. longisporum); the remaining strains showed a response with a tendency towards repellency. Most of the studied strains showed high virulence when the plants were treated with fungal conidia at a concentration of 1 × 10 mln spores/mL, causing 80–100% larval mortality on the 7th day. Strains Vl 5, Vl 78, and Vit 71 showed low virulence against the thrips (~50% larval mortality). These data should be taken into account when selecting strains and evaluating the effectiveness of entomopathogenic fungi against the western flower thrips.