Insecticide survival and behavioral avoidance in the lacewings Chrysoperla externa and Ceraeochrysa cubana

Insecticide impact on non-target species such as insect predators and parasitoids is an ever-growing concern in agriculture and recent studies have been shifting focus from lethal to sub-lethal effects since they may prevail in field conditions although more difficult to assess Synthetic insecticides are the main concern but the recent spread of biopesticide use in agriculture draws attention particularly the main botanical insecticide currently in use - azadirachtin Here we assessed the lethal and behavioral sub lethal response of predatory larvae of the lacewing species Chrysoperla externa and Ceraeochrysa cubana to two frequently used synthetic insecticides malathion and permethrin and to the bioinsecticide azadirachtin The recommended field concentration of the synthetic insecticides led to low survival time of lacewing larvae from both species in contrast with azadirachtin However all three compounds led to 100% mortality of the lacewing larvae from both species Insecticide repellence (i e avoidance without contact) was similar for both synthetic insecticides in both species but azadirachtin was a stronger repellent for C externa but not C cubana In addition insecticide irritability (I e avoidance after contact) occurred in both lacewing species to all three insecticides tested The notion that natural compounds are safer than synthetic compounds to non-target species is refuted in the present study which also detected significant irritability to all of the insecticides regardless of their origin and species-specific repellence elicited particularly by azadirachtin Therefore bioinsecticides should not be exempted from risk assessment and non-target sub-lethal effects should not be neglected when considering potential insecticide use in agriculture (C) 2010 Elsevier Ltd All rights reserved