CONTROL OF SOIL INSECT PESTS IN SWEETPOTATOES, 2012

A study was conducted on a commercial farm near Washington, St Landry Parish, LA to evaluate insecticides for management of sweetpotato soil insect pests including, the SCB, WG, RW. Six insecticide treatments, in addition to an untreated check, were assessed in a RCB design with 4 blocks and 1 replicate per block. Plots were four rows wide (44-inch centers) and 30 ft long. A CO2-pressurized backpack sprayer calibrated to deliver 15 gpa at 30 psi with a boom equipped with a TeeJet TP 8002 VS nozzle was used to apply insecticide treatments. Pre-plant treatments were applied on 31 May as a band in the open furrow. Furrows were closed within 2 hours of the application. Sweetpotato slips were transplanted on 5 June at a density of 1 slip per row foot. Lay-by treatments were applied on 27 June as a band along the row center, and beds were disked immediately after application. Subsequent insecticide foliar applications targeting cucumber beetle adults and lepidopteran pests were applied following standard regional production practices with commercial equipment. A total of 25 roots were randomly selected from the 2 center rows of each plot during harvest on 20 Sep. Treatment efficacy was evaluated by recording the presence of insect injury on each root. Injury data were compared using a linear mixed model (PROC MIXED, SAS Institute).