An oil-based formulation of Isaria fumosorosea blastospores for management of greenhouse whitefly Trialeurodes vaporariorum (Homoptera: Aleyrodidae)

Background: To date, emphasis has been placed on studying the virulence of Isaria fumosorosea conidia rather than the virulence of their blastospores. In the present study, a comparison was made of the efficacy of blastospores of I. fumosorosea (SFP-198) versus conidia against greenhouse whitefly (GWF) Trialeurodes vaporarioum nymphs and thermotolerance at 50°C. To improve thermotolerance and potency, the blastospores were suspended in corn oil with a wetting and an insect-filming agent. Results: Blastospores had similar efficacy against GWF nymphs to conidia in glasshouse conditions but had less thermotolerance than conidia. However, blastospores in corn oil had increased thermotolerance, comparable with that of conidia in corn oil. Application of SFP-198 blastospore oil-based formulation containing isotridecyl alcohol ethoxylated-3EO (TDE-3) and sodium alginate (SA) as adjuvants showed enhanced efficacy (95.7% mortality), compared with the SA-free oil formulation (72.8%) in 10days. Conclusion: SFP-198 blastospores can be used as an effective biological control agent, given their virulence against GWF, the enhanced thermotolerance in corn oil and the oil-based formulation studies to enhance their efficacy. Blastospores can be easily produced in liquid cultures in less than 4days, which is significantly shorter than using traditional solid cultures for conidial production.