Behavioral Response and Virus Vector Ability of Myzus persicae (Homoptera: Aphididae) Probing on Pepper Plants Treated with Aphicides

Behavioral response of the green peach aphid, Myzus persicae (Sulzer), to 3 different insecticides (cypermethrin, pirimicarb, and imidacloprid) was assessed on pepper plants, Capsicum annuum L., using electrical monitoring of aphid probing behavior. This technique enabled us to assess stylet penetration pathways as well as cell membrane punctures (potential drops). The effect of these insecticide treatments on potato virus Y (PVY) transmission by M. persicae also was tested. Pirimicarb and imidacloprid did not significantly affect probing behavior or PVY transmission efficiency when aphids were allowed a 10-min acquisition access period on infected insecticide-treated plants. Conversely, cypermethrin affected aphid behavior as well as PVY transmission efficiency. Aphids probing on cypermethrin-treated plants produced fewer (1.7 versus 3.3) and shorter (41 versus 152 s) penetrations than those probing on untreated plants. They also produced a lower number of potential drops (1.3 versus 4.2). Moreover, cypermethrin caused a paralysis of aphids within 2.5 min of exposure to the treated plants. Aphids were not able to subsequently inoculate healthy plants. However, when the acquisition access period was shorter than 2.5 min, aphids were able to efficiently transmit PVY despite the cypermethrin treatment of the virus source plant. The possible existence of an additional deterrent effect caused by cypermethrin on M. persicae and its implications in PVY epidemiology is discussed.