EVALUATION OF FOLIAR AND SOIL APPLIED INSECTICIDES FOR CONTROL OF COLORADO POTATO BEETLE AND WIREWORM ON POTATO, 2010

A field trial was conducted at the Tidewater Research Station in Plymouth, NC to evaluate the efficacy of foliar and soil applied insecticides for control of CPB and CW in potato. The trial was arranged in a RCB with 10 treatments and four replicates. Plots were 1 row by 9 m long planted on 1.8 m centers with unplanted guard rows. Seed pieces were planted on 12 Apr with 30 cm within row spacing; plants were managed according to local standard practices. In-furrow soil insecticides were applied immediately after seed pieces were placed in the furrow and before furrows were closed on 12 Apr. ‘Drag-off’ soil insecticide applications were made on 30 Apr; insecticide was applied to the soil surface directly over the row and incorporated with hilling discs. Foliar insecticide treatments were applied on 20 May. All insecticide treatments were applied with a CO2 powered backpack sprayer. Soil applications were made with a single nozzle boom equipped with DC25 cores and D4 discs delivering 15 gal/acre at 40 psi in the furrow or over the row. Foliar applications were made with a two nozzle boom equipped with DC25 cores and D3 discs delivering 30 gal/acre at 40 psi. Twenty stems per plot were evaluated for presence of CPB eggs, larvae and adults on 20 and 25 May and 3 and 16 Jun. All individuals were counted. Plots were harvested on 16 Jul using a one row tractor-driven chain digger. Tubers (n=50) were randomly collected from each plot and transported to the lab at NC State in Raleigh, NC. Tubers were washed and rated individually for wireworm damage. Treatment means were analyzed using the PROC MIXED in SAS (Version 9.1). When treatment differences were indicated, means were separated by LSD. Percent tuber damage data were arcsine square root transformed prior to analysis; untransformed means are presented here.