Susceptibility of mushroom dipteran larvae to four different groups of registered insecticides in Iran

Lycoriella auripila (Winn.) (Diptera: Sciaridae) and Megaselia halterata (wood.) (Diptera: Phoridae) are major pests of cultivated mushroom, Agaricus bisporus (Lge.) Imbach. They are controlled by chemical insecticides. It is necessary to study the toxicity of insecticides against the dipteran pests of mushrooms. This research investigated the toxicity of four commercial insecticides against the larval stage of the pests including pyriproxyfen and cyromazine from insect growth regulator group (IGRs), trichlorfon and cypermethrin from organophosphorus and pyrethroid groups respectively. The insecticides bioassay with sciarid and phorid larvae were conducted in the growing medium of mushroom. Insecticide treatments were incorporated into growing medium. The LC50 values of the insecticides were determined by emerged adults. The values of LC50 against the sciarid larvae for pyriproxyfen, cyromazine, cypermethrin and trichlorfon were 1.46, 31.15, 47.96 and 103.8 and for phorid larvae7.25, 189.65, 69.96 and 86.8 mg ai/L respectively. Pyriproxyfen was more toxic insecticide on larvae of both the pests.