Efficacy of Foliar Insecticides on Early Season Thrips and Aphids and Mid-Season Aphids in Cotton, 1986

Treatments were applied to plots that were 8 rows (40 inches wide) × 65 ft at the Macon Ridge Branch of the Northeast Research Station. The experimental design was a complete randomized block with 4 replications. Temik soil treatments were applied at planting (1 May) with a John Deere 7100 series planter, equipped with granular applicators. All plots received an infurrow treatment of Terraclor Super-X fungicide (1.0 + 0.25 lb (AI)/acre). Foliar insecticides were applied with a high clearance sprayer equipped with a compressed air system for spraying small plots and delivering 2.5 gal/acre with 2 X-3 hollow cone nozzles/row. The center 6 rows of all plots were sprayed in order to minimize drift. Early season application were sprayed on 2 Jun and evaluated 1, 3, and 7 days after treatment. Efficacy was evaluated by randomly collecting 10 plants from the center 2 rows of each plot. Plants were immediately placed in 1 qt glass jars and transferred to the lab for processing. A solution of water, soap, and bleach was added to the jars, and the samples in individual jars were washed through a series of mesh sieves (#100 and #40) in order to separate insects from plant samples. In the final step of processing, the contents collected on the #100 mesh sieve were washed into a Buchner funnel and collected on filter paper for observation under the microscope. A mid-season application was applied 15 Jun to evaluate effects on aphids. Insecticides were evaluated 7 days after treatment by randomly collecting 5 leaves from the upper third of plants in the center 2 rows of all plots. Leaves were placed in 1 qt glass jars and processed in the same manner as explained above. The test was over-sprayed with conventional insecticides at recommended rates for major pest control during Aug and Sep. The test was defoliated with Harvade (0.5 pt/acre) on 3 Sep. The center 4 rows of each plots were mechanically harvested on 15 Sep and 7 Oct. Yields were converted to lb seedcotton/acre.