Evaluation of Karate for Rice Water Weevil (RWW) Control, 1995

Abstract

Abstract Karate was evaluated for control of rice water weevil at the Rice Research Station, Crowley, LA. Collectively levied plots, 5 X 20 ft, were arranged in a RBD with 4 blocks and 8 treatments with sub-sample nesting within the block X treatment effect. Fertilizer was incorporated pre-plant and applied broadcast 3 wk post-flood at 90 lb (13-13-13) and 50 lb (21-0-0) N-P-K/acre, respectively. Plots were water seeded 29 May with pre-soaked ‘Cyprus’ rice at 138 lb seed/acre to Crowley silt loam and permanently flooded 8 Jun. Foliar applications of Karate were applied at 0.3 lb (AI)/acre. Furadan 3 G was applied at RWW threshold (5 larvae/sample) at 0.6 lb (AI)/acre using a hand-held shaker. Karate applications were made using a CO2 backpack sprayer delivering 15 gpa at 16 psi with 80015VS flat-fan spray nozzles on a 3 ft boom. RWW eggs were counted from 5 randomly selected plants per plot beginning 2 d post-flood then weekly until RWW threshold. Three randomly selected soil samples per plot were taken 26 Jun, and 3 and 11 Jul using a 4 X 4 in core sampler. Individual samples were washed through a funnel, fitted with wire screen, into a 35-mesh screen sieve. Collected rice water weevil larvae and pupae were floated in a saturated NaCl solution, and counted. Rough rice yield (lb/acre) was determined by hand-harvesting one random 3-ft2 sample per plot on 19 Sep. Moisture content of harvested grain was determined and standardized to 12% for determination of rough rice yield. All data were subjected to ANOVA. Experimental and sampling error terms for the RWW larval data were tested for homogeneity of variances, and pooled error terms were used to test the treatment effect when appropriate. Protected least significant differences (LSD) was used for treatment mean separation.