Compatibility and Toxicity of Lecanicillium lecanii with Insecticides against Cotton Aphids In vitro

Background: Lecanicillium lecanii is the most effective entomopathogenic fungus against all stages of sucking pests like aphids, whiteflies, scale insects, thrips and mealybugs. The compatibility of fungi with commonly used insecticides was investigated in this study.

Aim: To study the In vitro compatibility and toxicity of Lecanicillium lecanii with insecticides against cotton aphids.

Study Design: Completely Randomized Design.

Methodology: Six different insecticides were evaluated under in vitro conditions against L. lecanii by the poison food technique. The results showed that insecticides, viz., Dinotefuran 20 SG (0.006%), Afidopyropen 50 g/L DC (0.1%), Diafenthiuron 50 WP (0.06%) and Buprofezin 25 SC (0.05%), were rated as harmless and proved compatible with L. lecanii. Pyriproxyfen 10 EC (0.016%) and Tolfenpyrad 15 EC (0.03%) were moderately harmful to L. lecanii. Furthermore, the toxicity of insecticides alone and in combination with the entomopathogenic fungus L. lecanii against the cotton aphid, Aphis gossypii, was assessed by topical application bioassay under laboratory conditions.

Results: Cent percent mortality of A. gossypii was recorded with Diafenthiuron 50 WP (0.06%), Dinotefuran 20 SG (0.006%) and Afidopyropen 50 g/L DC (0.1%) at the recommended dose and their combination at half of the recommended dose with L. lecanii (1×107 conidia/ml) at 72 h after treatment. While minimum mortality was observed with the individual treatment of L. lecanii (1×107 conidia/ml).

Conclusion: This study suggests that the most suitable insecticides at half of the recommended dose, when combined with L. lecanii, can be effectively integrated into pest management programs.