Pw. Kidd et Dr. Rummel, EFFECT OF INSECT PREDATORS AND A PYRETHROID INSECTICIDE ON COTTON APHID, APHIS-GOSSYPII GLOVER, POPULATION-DENSITY, The Southwestern entomologist, 22(4), 1997, pp. 381-393
Cotton plants enclosed in predator exclusion cages were compared with
uncaged plants to examine the impact of predaceous arthropods on cotto
n aphid, Aphis gossypii Glover, populations. Effects of the pyrethroid
insecticide cyhalothrin (Karate(R)) on A. gossypii population develop
ment also were examined. Rapid increases in cotton aphid numbers, resu
lting in significant yield reductions, occurred on plants when predato
rs were excluded. These aphid populations declined only after exceedin
g the carrying capacity of the plants. Cotton aphid infestations on un
caged plants and on plants to which predators were introduced or allow
ed access were quickly controlled by naturally occurring predator popu
lations. When predators were excluded, cotton aphid numbers increased
faster and to higher levels on cyhalothrin treated plants than on untr
eated plants. The more rapid increase in aphid populations was not due
to the absence of predators, and was therefore attributed to a physio
logical interaction between cyhalothrin and cotton leaves or cotton ap
hids that resulted in increased aphid reproductive activity.