Abstract Cotton was planted in a Raymondville clay loam soil on 9 Apr at the Texas Agricultural Experiment Station Annex in Weslaco. Plots measured 2 rows (40-inch centers) by 40 ft, and were bordered by 2 rows of grain sorghum to reduce spra\ drift. Experimental design was a randomized complete block with 4 replications. Plants were oversprayed every 7 days with a mixture of 0.6 lb (AI) metalaxyl + 0.06 lb (AI)/acre cypermethrin to induce an outbreak of spider mites and aphids. Treatments were applied on 6 and 9 Jul with a CO2 sprayer at a rate oi 3 gal/acre finished formulation (3 mph, 40 psi, 3 TX1 hollow-cone nozzles/row). Aphids and mites were monitored by randomly collecting 5 leaves from each plot and counting all mites and aphids present on the leaves.