Control of Colorado Potato Beetle, 1996C

Abstract

Abstract This trial was located in a non-irrigated commercial potato field in the southern Red River Valley of the North. Plant spacing was 36 inches between rows and 12 inches between plants within rows. Treatments were arranged in a RCB design with 3 replications. Plots consisted of a single treatment row. Treated rows were separated by a row of untreated plants. For evaluating the treatments and determining plot size, counts of CPB larvae in each plot were recorded. Plots were of variable length (approximately 15-20 feet). The number of plants constituting a plot was determined on the basis of pre-treatment counts of CPB larvae so that plots averaged approximately 175 larvae, including small (instar 1-2) and large (instar 3^1) larvae. Small larvae predominated in the population (mean pre-treatment counts per plot: 138 small, 38 large). Treatments were applied with a CO2pressurized sprayer fitted with a Teejet 8O03-E fiat fan nozzle, delivering 60 gpa at 35 psi. Pre-treatment counts and folaii applications were made 14 Jul. Post-treatment counts of larvae were made 1 d after application. Percent control was calculated as (1-(post-treatment count/pre-treatment count)) X100. The data were subjected to ANOVA after arcsinV(x) transformation.