WESTERN FLOWER THRIPS CONTROL WITH RADIANT ON ROMAINE LETTUCE, 2010

The objective of the trial was to evaluate the efficacy of the Radiant applied at several rates and in combination with a biorational insecticide against western flower thrips on head lettuce under desert growing conditions. Romaine lettuce was direct seeded on 25 Sep, 2009 at the Yuma Valley Agricultural Center, Yuma, AZ into double row beds on 42 inch centers. Stand establishment was achieved using overhead sprinkler irrigation, and irrigated with furrow irrigation thereafter. Plots were two beds wide by 35 ft long and bordered by two untreated beds. Four replications of each treatment were arranged in a RCB design. Formulations and rates for each compound are provided in the tables. Foliar sprays were applied on 30 Oct and 10 Nov with a CO2 operated boom sprayer that delivered a broadcast application at 40 psi and 21.5 gpa through 2 TXVS-18 ConeJet nozzles per bed. An adjuvant, Penetrator Plus (1% vol/vol), was added to each spray mixture. The addition of the Penetrator Plus dropped the pH from 7.8 to 6.2. Numbers of WFT from 5 plants per replicate were recorded on each sample date. Relative WFT numbers were measured by removing plants and beating them vigorously against a screened pan (12 inch × 7 inch × 2 inch) for a predetermined time (15 s). A 6 inch by 6 inch sticky card was placed inside of the pan to catch the dislodged WFT. Sticky cards were then taken to the laboratory where adult and larvae were counted separately. Data were subjected to ANOVA and means were separated using an F-protected LSD (P ≤ 0.05).