Voracity of Coccinella undecimpunctata: effects of insecticides when foraging in a prey/plant system

Abstract

Coccinella undecimpunctata L. is a euryphagous predator established in Azores that offers interesting potential as a control agent in the context of integrated pest management (IPM). However, to further develop IPM against aphids, it is important to evaluate the effects that insecticides might have on voracity. Thus, we proposed to evaluate the effects of pirimicarb and pymetrozine on the voracity of 4th instar larvae and adults of C. undecimpunctata, under distinct scenarios of exposure to chemicals within a prey/plant system. Voracity of C. undecimpunctata was not significantly affected by pirimicarb or pymetrozine when treatments were directly sprayed on the predator; however, when insecticides were sprayed on the prey/plant system, the predator’s voracity was significantly increased. Results suggest that C. undecimpunctata does not detect the insecticide on the aphids and indicate that the increase in voracity may be due to a decrease in the mobility of insecticide-treated aphids, since their capture should be easier than highly mobile non-treated prey. The consequences of such increase in the voracity for IPM programs are discussed.