Relative susceptibility of red and green color forms of green peach aphid to insecticides

Field populations of green peach aphid, Myzus persicae (Sulzer), were collected from five produce fields near Yuma, Arizona. Three of the fields sampled contained both red and green-colored forms, while the remaining two fields contained only green-colored green peach aphids. Red-colored aphids were consistently more resistant to dimethoate and lambda-cyhalothrin, and usually more resistant to endosulfan than green-colored aphids collected from the same field. Slight differences in susceptibility to imidacloprid suggest that development of resistance is a possibility and justifies close resistance monitoring. Susceptibility to imidacloprid was not influenced by color form. We detected little or no differences in susceptibility to acephate, mevinphos or bifenthrin.