CONTROL OF RICE WATER WEEVIL WITH SEED TREATMENTS OF DPX-E2Y45, 2007

Seed treated with DPX-E2Y45 was evaluated for control of rice water weevil, a serious pest of rice in the mid-south, at the Rice Research and Extension Center. The field experiment was a RCB design with four replications of the four seed treatments of DPX-E2Y45, an untreated check, and a standard check on a Dewitt silt loam soil. Plots were nine rows (7 inch row spacing) × 25 ft and each plot was surrounded by levees to prevent movement of water and insecticides among plots. On 19 Apr, plots were drill-seeded at 95 lb/acre. Rice emerged to a stand on 29 Apr. Following a shaker-jar application of urea at 120 lb N/acre, the permanent flood was applied on 23 May. The standard check, KarateZ, was applied at eight d after permanent flood with a CO2 backpack sprayer calibrated to deliver 12 gpa at 22 psi through a 3 nozzle boom. On 13 and 20 Jun (21 and 28 d, respectively, after permanent flood), three, 4 inch diam. by 4 inch deep soil cores were removed from each plot. Rice roots from each core were thoroughly washed with a water hose equipped with a spray nozzle. The soil was washed into a 40 mesh sieve, briefly drained, and then agitated in a tub of salt water. The agitation caused the RWW larvae and pupae to float to the surface where they were recovered and counted. On 25 Jun urea at 30 lb N/acre was applied to plots with a Spyker spreader. On 31 Aug, rice was cut and bound with a small-plot binder and threshed with a Vogel thresher. Yields were adjusted to 12% moisture. RWW counts were subjected to ANOVA and means separated by LSD (P # 0.05).