Efficacy of Lorsban on Collards for Control of Cabbage Maggot, 1981

‘Georgia’ collards were seeded into 25-ft, two-row beds having 22-in. row and 16-in. interplant spacing on 20 May. The Ritzville silt loam (Calciorthidic Haploxerolls) soil had 1.6% organic matter and a pH of 6.2. Lorsban was spray banded over the planted row at 0.8, 1.6, and 3.2 fluid oz/1000 ft of row on 20 May and again on 8 July, 30 days preharvest. The seeder or tractor mounted TEEJET 8005E nozzles applied 80 gal/acre at 60 lb/in2 while movng at 2.1 mph. Experimental design was a randomized complete block with four replicates. Plots were sprinkler irrigated as needed with a rate of 0.375 acre-in/hr. Efficacy was determined at harvest by examining 16 roots per plot for insect damage. Phytotoxicity (stand loss) was determined at thinning, ca 4 weeks after planting. There were significant decreases in both the percentage of roots damaged and the degree of damage with increasing dosage. There was no difference in stand or yield.