Efficacy of Some Insecticides Against Cotton Aphid, Aphis gossypii and Its Associated Predators in Cotton Fields in Egypt

Abstract

Field studies were conducted to evaluate the efficiency of six insecticides against cotton aphid, Aphis gossypii in cotton fields located in Abu-hummus district, Beheira governorate, Egypt, during the 2023 and 2024 growing seasons. Additionally, the impact of these insecticides on the associated natural predators, the ladybird beetle, Coccinilla septempunctata, and the aphid lion, Chrysoperla carnea was also investigated. Results obtained showed that in both seasons, the highest initial reduction in cotton aphid was achieved by thiamethoxam, acetamiprid, and malathion, while buprofezin resulted in the lowest initial reduction rate in both seasons. Regarding residual efficacy in 2023, buprofezin, pymetrozine, and thiamethoxam significantly (P < 0.05) achieved the highest reduction rate, with means of 87.8, 84.5 and 79.1%, respectively. In 2024, buprofezin, pymetrozine, and malathion significantly (P ˂ 0.05) produced the highest significant residual reduction rate of 87.5%, 85.2%, and 80.3%, respectively. In terms of environmental safety, acetamiprid and malathion exhibited the strongest negative initial and residual effects on ladybird beetles in both seasons. Conversely, thiamethoxam and buprofezin showed the least adverse effects on this predator. For the aphid lion, malathion and etofenprox caused the highest initial and residual reduction rates, whereas buprofezin and thiamethoxam demonstrated the lowest toxicity. These results indicate that studying the impact of insecticides on natural enemies should receive attention along with the efficiency studies on insect pests to ensure sustainable integrated pest management (IPM) practices.

Keywords:

Aphid lion, IGRs, insects, IPM, ladybird beetle, neonicotinoids, selectivity.