Control of Rice Water Weevil with Dimilin 2 L in a Drill-Seeded, Delayed Flood Culture at Eagle Lake, 1997

Abstract

Abstract The experiment was conducted at the TAES Western Area Operations at Eagle Lake. The experiment was designed as a RCB with 8 treatments and 4 replications. Each plot was 15 ft X 8 ft and surrounded by a metal barrier to prevent movement of insecticide and fertilizer. Plots were drill planted (7.5 inches between rows) on 15 Apr at 80 lb seed/acre. Soil type was Nada. Plots were fertilized at planting with 45 lb nitrogen/acre, 38 lb phosphorus/acre, and 40 lb potassium/acre. Rice emerged through soil on 25 Apr. From emergence of rice through soil to application of the permanent flood on 22 May (27 d after application of the permanent flood), plots were flushed irrigated (24 h temporary flood then drain) as needed. On 24 Apr, plots were sprayed with Wham EZ at 1 qt/acre, Bolero 8 EC at 2 pt/acre, and Facet 75 DF at 0.25 lb/acre. On 16 May, plots were sprayed with Wham EZ at 3 qt/acre. Facet 75 DF at 0.25 lb/acre, and Londax at 0.05 lb/acre. On 21 May, plots were fertilized with urea at 60 lb nitrogen/acre. On 24 May (2 d application of the permanent flood), selected plots were sprayed with Dimilin 2 L at the rates shown in the table. On 2 Jun (lid after application of the permanent flood), selected plots were sprayed with Dimilin 2 L at the rates shown in the table. Sprays were applied with a 4 nozzle (tip size 800067, 50 mesh screens), hand-held spray rig pressurized with CO2. Final spray volume was 16.0 gpa. On 5 Jun (14 d after application of the permanent flood), selected plots were treated with Furadan 3 G at 20 lb/acre using a hand-held shaker jar. On 13 Jun, plots were sprayed with Londax at 0.05 lb/acre. On 25 Jun, plots were fertilized with urea at 50 lb nitrogen/acre; thus, total nitrogen applied during the entire growing season was 155 lb/acre. On each of 12 Jun and 25 Jun (21 and 34 d, respectively, after application of the permanent flood), five 4-inch diam X 4 inch deep soil cores (each containing at least 1 rice plant) were removed from each plot. Rice plants in cores were washed and immature RWW recovered from the roots. On 12 Jul, plots were sprayed with Sevin XLR Plus at 1 qt/acre to control rice stink bug. The middle 8 rows of each plot were harvested on 26 Aug (123 d from emergence of rice through soil). Yields were adjusted to 12% moisture. Insect counts were transformed using x + 0.5 and all data analyzed by 2-way ANOVA and DMRT.