EVALUATION OF PREPLANT AND LAYBY INSECTICIDES FOR CONTROL OF SOIL INSECTS IN SWEET POTATOES, 2009

Trials were conducted at the LSU AgCenter Sweet Potato Research Station, Chase, LA in 2008, to evaluate the efficacy of pre-plant and lay-by insecticides for control of soil insects. All pre-plant insecticide treatments were applied the day preceding transplanting. Sweet potato transplants were planted at a rate of 1 plant/ft in plots of 3 rows (centered on 42 inches) × 25 ft on 12 June. Treatments were arranged in a RCB design and replicated four times. Pre-plant insecticides were applied as a band along the row center, and the beds were disked immediately after application. A CO2-pressurized backpack sprayer was used (30 lb psi) with two nozzles (Tee-Jet 8002vs) calibrated to deliver 15 gpa. Lay-by insecticides were applied with the same equipment, 4 wk after planting as a band along the row center, and the beds were disked immediately following application. At harvest, roots from the middle row were dug and 25 roots per plot were chosen at random and evaluated for insect damage after washing. Total insect damage (cucumber beetle, white grub, sugarcane beetle) and sugarcane beetle only damage are reported. All data were subjected to ANOVA and means separated according to LSD (P > 0.05).