Evaluating Efficacy and Economic Profitability of Preventive Insecticidal Seed Treatments in Cotton

Research was conducted to evaluate biological and economic performance of various insecticidal seed treatments using multi-location field studies. Field trials were conducted at six locations (Lubbock, Kress, Brownfield, Muleshoe, Mercedes, College Station) in Texas and two (Artesia and Las Cruces) in New Mexico. Trials were designed as an RCB with 5 treatments (Untreated check, Gaucho 600, Cruiser 5FS, Aeris, and Avicta Elite cotton) and 4 replications. To estimate thrips densities, plant samples (10 plants/plot) were collected at cotyledon, 1, 2, 3, and 4 true-leaves stages. Plant samples were brought to the laboratory in glass mason jars containing 75% ethyl alcohol. Samples were processed using a washing technique and the number of thrips adults and immatures in each sample were counted using a dissecting microscope. Thrips damage ratings were taken at 1 to 4 true-leaves stages using the scale 0-5 (0 = no damage and 5 = severe damage).

Thrips pressure varied drastically across locations. Kress site experienced the highest thrips pressure while the lightest thrips pressure was observed at Brownfield.  At Kress, plots treated with Gaucho 600, Cruiser 5FS, Aeris, and Avicta Elite cotton sustained significantly fewer thrips compared to untreated check throughout the cotyledon to 4 true-leaves stages. Overall, significantly higher thrips damage was observed in untreated plots compared to treated plots at locations with high (above threshold) thrips pressure. On the other hand, no significant thrips damage was observed at sites with low (below threshold) thrips pressure. Field trials are being managed using local agronomic practices and will be taken to the yield. Lint and seed yields will be determined and economic returns from seed treatments will be estimated across low and high thrips pressure scenarios.