Efficacy of Selected Insecticides and Insecticide Combinations Against Heliothis Spp. and Boll Weevil on Cotton, 1987

A small-plot evaluation was conducted at the Red River Research Station, Bossier City, La., to determine the efficacy of various insecticides and combinations in controlling boll weevil and Heliothis spp. on cotton. Plots were 4 rows × 36.6 m and were arranged in a randomized complete block with 4 replications. Cotton was planted 5 May on 1.02-m centers. Insecticides were applied with a high-clearance sprayer equipped with a CO2 system for spraying small plots. Insecticides were applied in 11.4 liters of water/acre at 60 psi with TX-3 hollow-cone nozzles spaced 50.8 cm apart. Treatments were applied on 20 and 27 Jul and 3 Aug. All plots were oversprayed with Penncap-M 2M, 0.25 lb (AI)/acre, on 24 Jun and with Guthion 2L, 0.25 lb (AI)/acre, on 3, 16, 24, and 31 Jul for weevils. Following the last observation on 6 Aug, the entire test was oversprayed with a pyrethroid on 8, 16, and 22 Aug. Plant damage was monitored 2 - 3 days following each treatment application by examining 25 squares/plot. Yields were determined by mechanically harvesting the center 2 rows from each plot on 24 Sep and 5 Oct.