This paper summarizes cotton insect control evaluations at Stoneville, Mississippi, from 1961 through 1984. Studies over the 24-year period are covered in three phases. Phase one reports on the insect pests causing yield losses in these tests. Major insect pests over the years have been the boll weevil and the Heliothis complex. During most of the 60's the boll weevil was the most important, but beginning in 1969 there was a change with the Heliothis complex becoming the most important in terms of losses caused to the cotton crop. Minor pests have included the tarnished plant bug, fall armyworm, beet armyworm, spider mites, cabbage looper, aphids, whiteflies, and thrips. Estimated annual losses in yield due to insect pests in these tests have ranged from a low of 6.5% in 1982 to a high of 75% in 1978.

Insecticidal control methods are highlighted in phase two. Methods for control of insects to prevent losses in yield have included cultural practices, resistant varieties, attractants and trap crops, and biological. However, in the long run, when infestation levels reach a certain point, the only satisfactory method of control has been and will continue in the foreseeable future to be insecticides. Over this 24-year period the main types of insecticides have changed from chlorinated hydrocarbons, carbamates and organophosphates, to mixtures of chlorinated hydrocarbons + organophosphates, to mixtures of organophosphates, to synthetic pyrethroids.

Phase three presents the results of the insecticide controls used in these tests in terms of yield. Recommended insecticides used as standards have resulted in annual average yields ranging from a minus 139 pounds per acre in 1966 to an increase of 1321 pounds of seed cotton per acre in 1978 as compared to yields in untreated checks. Recommended or better (including experimental compounds) treatments have resulted in average yield increases ranging from 94 pounds per acre in 1965 to 1561 pounds of seed cotton per acre in 1978 over the checks. As individual materials, one or more carbamates and organophosphates have been involved in tests 23 of the 24 years; biological insecticides 13 years; chlorinated hydrocarbons and synthetic pyrethroids 10 years; and formamidines 5 years. By class of insecticide, the synthetic pyrethroids have averaged the greatest increases in yield followed by cafbamates, organophosphates, formamidines, chlorinated hydrocarbons, and biological insecticides in that order. Results are also summarized for several individual materials as well as combinations and mixtures which have been involved in tests over several years.