EVALUATION OF RADIANT FOR CONTROL OF LEPIDOPTEROUS LARVAE ON FALL BROCCOL, 2005

The objective of the study was to evaluate the efficacy of the new compound Radiant relative to standard materials used against lepidopterous larvae on head lettuce under desert growing conditions. Lettuce was direct seeded on 8 Sep 2005 at the Yuma Valley Agricultural Center, Yuma, AZ into double row beds on 42 inch centers. Stand establishment was achieved using overhead sprinkler irrigation, with furrow irrigation used thereafter. Plots were two beds wide by 45 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. Sprays were applied on 24 Sep, 6 Oct and 17 Oct. The applications were made with a CO2 operated boom sprayer at 60 psi and 21 gpa. A broadcast application was delivered through 2 TX-18 ConeJet nozzles per bed. An adjuvant, Dyne-Amic (Helena Chemical Co.), was applied at 0.125% v/v with all treatments. Evaluation of efficacy was based on the number of live larvae per plant. Ten plants per replicate were destructively sampled on each sample date. The sample unit consisted of examination of whole plants for presence of small and large BAW, DBM and CL. For BAW and DBM, larvae were considered small if < 5 mm in length, large if > 5mm in length. For CL, larvae were considered small if < 10 mm, large if > 10 mm. Treatment means were analyzed using a 1-way ANOVA and means separated by a protected LSD (P < 0.05).