Survival, development and reproduction of Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) under effects of insecticides used in tomato plants.

Abstract

Agriculture depends on the correct use of different methods for pest control, however the cultivation methods adopted for Solanaceae demands numerous pesticide applications. These products can be either harmful or selective to beneficial organisms, such as Coccinellidae predators. The aim of this study was to assess the physiological selectivity of insecticides, registered for tomato pest control, on Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae). The maximum recommended field dosage of the insecticides spinetoram, spiromesifen, methoxyfenozide, metaflumizone, tebufenozide and methomyl was used. They were sprayed on eggs, third instar larvae, pupae and adults of H. axyridis using Potter´s tower; control treatment consisted of water. Methoxyfenozide didn't reduce any biological feature of the predator. Spiromesifen only reduced survival over time when sprayed on third instar larvae. Spinetoram shortened larval period and reduced survival of adults. When sprayed on larvae, metaflumizone reduced larval survival. Tebufenozide reduced egg viability, pupal period and larval survival over time. It is concluded that methoxyfenozide, spiromesifen and spinetoram are the least toxic to H. axyridis, and their usage should be prioritized in integrated pest management (IPM) programs; both tebufenozide and metaflumizone are harmful to some important biological features of the predator. Methomyl is highly toxic in controlled conditions, so its toxicity to H. axyridis should be confirmed in field and greenhouse tests, we also suggest further studies with the other compounds in different concentration and route of exposure.