John R. Ruberson, Sharad C. Phatak, W. Joe Lewis INSECT POPULATIONS IN A COVER CROP/STRIP TILLAGE SYSTEM Proc.Beltwide Cotton Conf.(1997) 2:1122-1124

Abstract

Conservation tillage and the use of cover crops can provide multiple benefits to growers, but the effects of these practices on insect populations in cotton are not well defined. A replicated large-plot ( I acre each) test was undertaken to evaluale 5 different cotton production systems: ( I ) conventional plowing and cultivation; (2) growth of a rye cover crop, followed by conventional tillage prior to planting cotton; (3) growth of a crimson clover cover crop, followed by conventional tillage prior to planting cotton;(4) growth of a rye cover crop, and planting of cotton into row-tilled strips; and (5) growth of a crimson clover cover crop followed by planting of cotton into row-tilled strips. These treatments were sampled twice weekly for insects. The results of only treatments 1, 4, and 5 are reported here. None of the treatments had appreciable effects on heliothine egg orlarval populations. Cotton aphid populations were also similar among treatments dunng July, but increased significantly in the conventionally-tilled plots in August. Natural enemy populations were similar among treatments, with the exception of the red imported fire ant, which was more abundant in the conservation tillage plots than in conventionally-tilled ones. No correlations were observed between pest and natural enemy populations. Yield variation was unrelated to insect populations, but was influenced by tillageand cover crops.