Chemical Trials and Effects on Arthropods in Celery, 1992

Celery was transplanted in a sandy loam soil on 3 Sep at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in a randomized complete block design. Weekly application dates included 15, 22, 29 Oct, 5, 12, 19, 25 Nov and 3, 10 Dec. All chemicals were applied by a tractor-mounted boom sprayer operated at 100 psi. Nozzles were 4 per bed and carrier (H20) was at 100 gal/acre. Disc-type cone nozzles incorporated D3 orifice discs, #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam®) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5.5 × 11 inch trays/replicate when the plants reached a suitable height. Actual sampling dates were 20, 28 Oct, 4, 11, 18, 23 Nov and 2, 9 Dec. The number of dead adult parasites of Liriomyza species were recorded in the same manner and on the same dates listed for pupal counts. Evaluation of Lepidoptera populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (14 Dec). Beet armyworm and black cutworm damage was recorded separately.