Two small-plot, replicated experiments and six largeplot, non-replicated experiments were conducted over the two year period of 1981 and 1982 to determine the effects of foliar applications of chlordimeform on cotton yields. Treated cotton received 4 or 6 applications of chlordimeform 0.125 lb/A at 5-8 day intervals, beginning at the six-leaf stage of the cotton. Pest management treatments were held constant in each experiment and pests were kept below established economic thresholds. The small plots were 4 rows wide by 50 feet in length and were replicated 8 times. Plots in the non-replicated field experiments were 2050 acres in size.

Results of the two small-plot, replicated experiment were very similar with numerical but not statistically significant (5% level) yield increases occurring in the chlordimeform treatments. Four applications produced lint yield increases averaging 140 lb/A (8.4%). Six applications produced lint yield increases averaging 132 lb/A (7.9%). Acephate 0.25 lb/A was also applied in four applications and six applications in the same manner as the chlordimeform treatments. Four applications of acephate resulted in an average yield increase of 76 lb/A (4.6%); six applications resulted in an average yield increase of 151 lb/A (9.1%). The six application treatment of acephate in the 1981 experiment was the only treatment resulting in a statistically significant yield increase.

Results of the large-plot, non-replicated experiment varied greatly in 1981 and 1982. In 1981 lint yield increases of 175 1 b/A (17.9%), 135 lb/A (12.9%) and 102 lb/A (9.2%) occurred in the 3 experiments, for an average increase of 137 lb/A or 13.3%. In 1982 in 3 experiments chlordimeform-treated cotton yielded an average of only 5 lb lint/A more than untreated cotton with differences of +6, +12, and -2 lb lint/A.