Chemigation for Onion Thrips Control, 1988:

Polyethylene drip irrigation tubing with 18-inch emitter spacings was buried 8 inches deep in 40-inch beds and onions direct seeded to the beds on 29 Oct 1987. Soil was a sandy clay loam and plants were spaced in 2 rows/bed, 6 inches from the center of the bed with 3 inch in-row spacing. Onion plants were surveyed weekly after 1 Jan, and treatments were begun on 29 Feb after thrips populations reached levels greater than 5/plant. The experimental design was a randomized complete block with 4 replicates. Treatments consisted of untreated checks and applications of oxamyl either through the drip irrigation system or by a hand-held pressurized 1-nozzle sprayer at a rate of 0.5 lb (AI)/acre. Total volume of water with which oxamyl was applied through the drip system was 2,500 gal/acre and for the sprayer was 185 gal/acre. Three separate treatments were made; 29 Feb and 10 and 21 Mar. Surveys for thrips were conducted on 7 and 25 Mar by counting all live thrips on 3 plants/plot. Numbers were transformed to log10(x + 1) and subjected to ANOVA and DMRT.