Insecticide Control Demonstration of Spider Mites On Cotton, 1983

The objective of this demonstration was to evaluate currently recommended insecticides for spider mite control and to determine if soybean oil (SBOC Standard) is better suited than water as a carrier of insecticides. ‘Delcot 390’ cotton was planted 21 May on the Univ. of Missouri Delta Center Lee Farm near Portageville (Pemiscot County), Mo. Eight row plots 100 ft long were replicated four times in a randomized complete block design. Insecticides were applied on 2 Aug. Water carried insecticides were applied with a four-row boom at a rate of 2.38 qt per acre (8.8 mph, 20 lb/in2, one Micro-max nozzle #20 orifice per row, 2,000 rpm) through an air pressurized system. Ten leaves exhibiting spider mite symptoms were picked per plot, bagged and brought back to the laboratory where mites per leaf were counted with the aid of a microscope. Plots were sampled at 2, 7, and 14 day intervals to determine the number of live mites present per leaf.