Acão de inseticidas organofosforados utilizados no controle de Leucoptera coffeella (Guérin-Mèneville) (Lepidoptera: Lyonetiidae) sobre o ácaro predador Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae)

Abstract

Chemical control has been preferentially used to suppress pests by farmers mainly due to low price of the products and immediate action on target organisms. However, wide action range of the compounds, undesirable effects on non target organisms and the contamination of the environment are among the disadvantages of this method of control. This study evaluated the action of the insecticides chlorpyrifos, disulfoton, ethion and methyl-parathion, normally used to control the coffee leaf-miner, Leucoptera coffeella (Guérin- Mèneville), on the predaceous mite Iphiseiodes zuluagai Denmark & Muma, a control agent of the phytophagous mites Oligonychus ilicis (McGregor) and Brevipalpus phoenicis (Geijskes) in coffee plantation. Discriminatory concentrations (LC99), established on the 3rd instar of L. coffeella, by means of the method of dry insecticide residues impregnated in filter paper, were used to verify the selectivity of the insecticides on the predaceous mite. The insecticide chlorpyrifos caused 100% of mortality in I. zuluagai. Ethion and methyl-parathion showed mortality of 34% and 19%, respectively. Disulfoton presented the highest selectivity for the mite, with no lethal action on the predator. The different effects found on the insecticides' action show that it is possible to use the selective insecticides in coffee plantation to preserve populations of I. zuluagai, thus favouring the biological control on phytophagous mite.