EFFECT OF CYHALOTHRIN ON FIELD POPULATIONS OF THE COTTON APHID, APHIS-GOSSYPII GLOVER, IN THE TEXAS HIGH-PLAINS

Cotton aphid, Aphis gossypii Clover, population densities in untreated cotton plots were compared with those in plots receiving one and two applications of cyhalothrin (Karate(R)) and one application of dicroto phos (Bidrin(R)). The cyhalothrin applications were timed to simulate typical treatment(s) for bollworm, Helicoverpa tea (Boddie), infestati ons and the dicrotophos application targeted beneficial arthropods. Ra pid increases in aphid population densities occurred within 2 wk of cy halothrin applications, resulting in significant yield reductions. Aph id numbers in dicrotophos treated plots were not significantly differe nt from those in untreated plots on any sample date. Increases in aphi d numbers did not appear to be due to reductions in predator populatio ns, and predator populations appeared to increase only in response to increasing aphid populations.