Cotton Aphid Control, Chillicothe, TX, 1981

Dryland-grown cotton was planted on Jun 25 at the Texas Agricultural Experiment Station, Chillicothe, TX. Six treatments were replicated 3 times in a randomized complete block design. Plots were 6 rows wide by 24.4 m long and 102 cm between rows with 7.6-meter alleys separating replications. Spray applications were made with a 3-point hitch power takeoff sprayer mounted on a tractor traveling 4.12 kmph and delivering 86.0 liters total solution per hectare at 345 kPa. One application of each insecticide was made Aug 13. Aphids were counted on 15 terminal leaves and on 10 mid-height plant leaves. Leaves were picked about every 1 m of row. A sample was taken on Aug 13 just prior to treatment and post treatment samples were taken on Aug 17, 20 and 28 (3.5, 7, and 15 days post-treatment, respectively). Rainfall on Aug 16, 17 and 27 was 2.03, 1.27 and 2.80 mm, respectively. In each plot cotton from 4 row m was hand picked for yield on Nov 25. On each sampling date, 50 sweep samples were taken for beneficial insects.