Effectiveness of Bacillus Thvringiensis Formulations for Control of Lepidopterous Pests on Fall Cabbage, 1992

‘Blue Vantage’ cabbage plants were transplanted on 25 Aug into a Bernow series fine, sandy loam soil at the Wes Watkins AREC in Lane, OK. Plots consisted of 2 12 ft rows on 36 inch centers with each treated plot separated by an untreated bed and 12 ft buffers within rows. Transplants were spaced 12 inches between plants within each row and fertilized at recommended levels and irrigated as needed through a trickle system. Treatments were replicated 4 times in a randomized complete block design. Insecticides were applied with a CO2-powered backpack sprayer equipped with 2 hollow cone TX-18 nozzles/row. The sprayer was calibrated to deliver 46.6 gal/acre at 2 mph using 40 psi. Treatments were applied on 17, 24, 29 Sep, 5, 13, 21, 27 Oct, and 2 Nov. Insecticide efficacy was assessed by counting CL larvae and eggs, parasitized CL, DBM larvae, YSA larvae, BAW larvae, CWW larvae, and CSCW larvae on 8 randomly chosen plants/replicate on 12 dates. Counts were always made prior to spraying on those dates that are the same. Plots were harvested as ready on 5, 12 and 19 Nov and individual heads were weighed and graded using the following scale: 1 = no wrapper leaf damage, no head damage; 2 = wrapper leaf damage, no head damage; 3 = wrapper leaf damage, light head damage; 4 = wrapper leaf damage, moderate to severe head damage. Heads rated 1 or 2 were considered marketable according to USDA standards. Data were transformed [log (x + 1)] before analysis where appropriate. Data were analyzed using analysis of variance (ANOVA, SAS 1988) and means were separated using Ryan’s Q test.