EFFICACY OF Torac Tank-MIXTURES against WESTERN FLOWER THRIPS ON ROMAINE LETTUCE, 2013

Abstract

The objective of the trial was to compare the efficacy of Torac tank-mixtures to industry standards for western flower thrips control on romaine lettuce. Romaine ‘Big Green COS’ was direct seeded on 27 Nov, 2012 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. All foliar sprays were applied on 1, 13 and 26 Feb. The applications were made with a CO2 pressurized boom sprayer that delivered a broadcast application at 40 psi and 22.5 gpa through 2 TXVS-18 ConeJet nozzles per bed. An adjuvant Dyne-Amic (Helena Chemical Co.), was applied at 0.25% to all treatments. Numbers of WFT from 5 plants per replicate were recorded at various sample dates following each application (DAT). Relative WFT numbers were measured by removing plants and beating them vigorously against a screened pan (12 inch x 7 inch x 2 inch) for a predetermined time (10 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. Because of heterogeneity of mean variances, data were transformed using a log10 (x + 1) function before analysis and subjected to ANOVA; means were compared using an F-protected LSD (P ≤ 0.05). Means from non-transformed data are presented in the tables.