Insecticide Control of Sweetpotato Whitefly on Broccoli and Lettuce, 1992

Abstract

Abstract The studies were conducted at the USDA-ARS Irrigated Desert Research Station at Brawley, CA in randomized complete blocks design with four replicates. Hybrid broccoli, cv. ‘Packman’ at 7.6 seeds/ft seed row, and head lettuce, cv. ‘Empire MI’ at 8.5 seeds/ft seed row, each in separate plots, were planted on 25 Sep. Plots of each crop were two rows (beds) in 40-inch row spacing and 20 ft long. Seed rows of each crop were spaced 20 inches apart on a bed. Plots were separated by two fallow rows and blocks separated by 20-ft fallow alleys. Treatments were (1) untreated, (2) weekly foliar application of Capture 0.08 lb Al/acre and Monitor 0.75 lb Al/acre, (3) weekly foliar application of mixture of Danitol 0.2 lb Al/acre and Monitor 0.75 lb Al/acre, (4) soil application of Admire 0.345 lb Al/acre at planting, (5) treatment 4 plus foliar application once of Admire 0.345 lb Al/acre 3 weeks after planting, (6) treatment 4 plus foliar application once of Admire 0.345 lb Al/acre 4 weeks after planting, (7) treatment 4 plus weekly foliar application of treatment 2 beginning on week 4 after planting, (8) treatment 4 plus weekly foliar application of treatment 3 beginning on week 4 after planting, (9) weekly foliar application of CGA 245704 0.044 lb Al/acre. Weekly foliar applications of treatments 2, 3 and 9 were initiated on 7 Oct (7 days after plant emergence or 12 days after planting). A total of seven applications was made. Foliar applications of treatments 5 and 6 were made on 14 and 21 Oct, respectively. Five weekly applications of treatment 7 and 8 were made beginning on 21 Oct. Treatments were applied with a backpack sprayer to deliver 29 gal/acre. SPWF immatures were counted on each side of a leaf disk of 3.14 cm2 taken from each fourth leaf from plant terminals. Pretreatment counts were made on leaf discs from ten leaves on 6 Oct, 1 day before the first treatments were applied. Thereafter weekly leaf samples were taken 6 days after each application and 1 day before the next application. The last samples were taken on 29 Dec. Crops were harvested three times on 4, 11 and 18 Jan 1993.