Efficacy of Pyrethroids and Lannate on Lepidopterous Larvae in Lettuce, 1995
Abstract Lettuce was direct seeded into double-row beds on 9 Sep at the Yuma Valley Agricultural Center, Yuma, Az. Each plot consisted of four, 30 ft long beds spaced 42 inches apart and bordered on each side by an untreated bed. Plots were arranged in a RCB design with 4 replicates. Foliar applications were made on 22 and 30 Sep and with a hand-held CO2 sprayer operated at 60 psi, delivering 20 gal/acre. Spreader-sticker (Kinetic) was included in all spray treatments at a rate of 0.25% of the total volume. Insecticide efficacy was determined by counting the total number of small (1st and 2nd instars) and large (>2nd instar) BAW and CL larvae on 20 randomly selected lettuce plants per replicate. Insect counts were conducted the day of application, 22 and 30 Sep, and at 3 days after treatment, 30 Sep and 3 Oct. Treatment differences among means were estimated with the Ryan-Einot-Gabriel-Welsch multiple F test.