Efficacy of Fipronil for Thrips Control on Onions, 1996

Onions were planted on 42 inch beds in double rows near Somerton, AZ. The test was a RCB design consisting of four replicates. Each plot was 2 beds wide by 25 ft, bordered on each side by 2 buffer beds. Applications were made using a backpack CO2 with two TX-10 hollow cone nozzles per bed. The sprayer was calibrated to deliver 20 gpa at 45 psi. Treatments were applied on 19 Apr 2 and 26 Apr. All treatments included Kinetic non-ionic surfactant at 0.1% v/v. Evaluations were made by cutting and bagging 16 green onion tops per plot. These samples were taken to the laboratory where they were rinsed with a soap/water solution and filtered through filter paper. The thrips were then counted on the filter paper under dissecting microscopes. Evaluations were made 3 and 7 days after each application (22 Apr, 26 Apr, 29 Apr and 3 Mar). Differences among treatments were separated using ANOVA and an F protected LSD.