Insecticides with Disyston 15G as Safener for Command Herbicide on Cotton in Mississippi, 1994

Abstract

Abstract Insecticides were applied in-furrow with different rates of Disyston 15G in a split block statistical design with Command and Cotoran herbicides as main plots and insecticides as subplots. Insecticide treatments were paired across herbicides, and applied in 2 row plots randomized within each of 4 replications. Cotton was planted at the Plant Science Research Farm, Mississippi State, MS, in Marietta sandy loam soil with 10 lb of Terraclor SuperX fungicide per acre on 15 May with a John Deere 7100 Maxemerge planter equipped with Almaco cone planters for seed application and belt cone planters for granule application. Soil parameters were: pH 8.0, OM 1.13%, 9.3% clay, 29.5% silt and 61.2% sand. Preemergence herbicides were applied at a rate of 0.75 lb (AI)/acre (Command) and 1.0 lb (AI)/acre (Cotoran) at a volume of 20 gpa with a tractor mounted flat boom equipped with 8003 flat fan nozzles spaced at 19 inches positioned 12 inches above the ground at a speed of 4 MP. The herbicides were lightly incorporated by dragging a chain behind the sprayer. Application pressure was 35 psi. Thrips were counted by destructive plant sampling followed by washing the thrips from the plants and counting them with the aid of dissection microscopes. Plants collected for thrips samples were measured from the cotyledonary node to the apical meristem. Phytotoxicity ratings were made by rating each plot for white, red and yellow coloration on the basis of 0 (none) to 5 (all plants colored) and adding these values together. Rainfall recorded during the test was 0.5 inches on 15 May, 0.18 inches 4 Jun and 0.6 inches 8 Jun.