Laboratory Evaluation of New Molecules of Insecticides against Micromus igorotus Banks (Neuroptera: Hemerobiidae)

Abstract

An investigation was carried out during 2007-08 at Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad to evaluate new molecules of insecticides against the predatory brown lacewing, Micromus igorotus Banks in laboratory conditions. Insecticides showed distinct deleterious effect on different life stages of M. igorotus. Emamectin benzoate was highly toxic to all the stages of the predator by recording least LC₅₀ values ranging from 0.001032-0.00314. Thiodicarb was the least toxic to eggs (LC₅₀: 0.159262) and grubs (LC₅₀: 0.007240), profenophos was safe to pupa (LC₅₀: 0.026570), while indoxacarb was 505050 the safest to adult (LC₅₀: 0.003115). Relative toxicity of chemicals when compared to their field concentration against target pest revealed that safety margin was the lowest for profenophos to eggs and grubs, followed by methomyl. Among the insecticides tested, emamectin benzoate was highly toxic to all stages of M. igorotus, while thiodicarb was the least toxic to eggs and larval stages, however, profenophos and indoxacarb were the least toxic to pupae and adults, respectively.