Toxic effects of pesticides on the green lacewing, Chrysoperla zastrowi sillemi (Esben-Peterson) (Neuroptera, Chrysopidae)

Abstract

The study evaluated the toxic effects of quinalphos 25% EC, deltamethrin 2.8% EC, bifenthrin 8% SC, thiamethoxam 25% WG, thiacloprid 21.7% SC, thiamethoxam 12.6% + lambda-cyhalothrin 9.5% SC, propargite 57% EC, hexythiazox 5.45% EC, fenpyroximate 5% EC, and spiromesifen 22.9% SC on various life stages of Chrysoperla zastrowi sillemi (Esben-Petersen) in laboratory conditions, including eggs, larvae (1st, 2nd and 3rd instars) and adults. The results showed that quinalphos, deltamethrin and spiromesifen had significantly high ovicidal activity percentages of 56, 43.3 and 42.7 per cent, respectively, on C. z. sillemi eggs. The toxicity of the pesticides on C. z. sillemi larvae gradually increased over time after application and decreased with the increasing life stage of the larvae. Quinalphos and deltamethrin exhibited 100 per cent mortality across all larval stages of C. z. sillemi. Similarly, quinalphos and deltamethrin caused 100 per cent adult mortality after 24 hours of application, followed by thiamethoxam + lambda-cyhalothrin and thiacloprid, (which showed 92 and 60% mortality, respectively, after 96 hours). However, pesticides such as bifenthrin, thiamethoxam, hexythiazox, fenpyroximate, and propargite did not exhibit significant acute toxicity on eggs, larvae, and adults of C. z. sillemi. Furthermore, the pesticide-treated adults were evaluated to determine sub-lethal toxicity effects on the pre-oviposition period, post-oviposition period, fecundity, fertility, adult emergence, and adult longevity. The findings indicated that thiamethoxam + lambda-cyhalothrin, spiromesifen, thiacloprid, and propargite-treated adults experienced reduced longevity, fecundity, and fertility.