Control of Cabbage Looper and Diamondback Moth on Cabbage, Spring, 1993

Abstract

Abstract Six week old cabbage plants were transplanted into a Bernow series sandy loam soil on 29 Mar at the Wes Watkins AREC Lane, OK. Plots one row wide by 4.6 m long were arranged in a randomized complete block design with four replications. One unplanted row between rows and 3 m within rows served as spray buffers. Doublerow beds were spaced 0.9 m apart with 30 cm between plants within rows. Standard cultural practices were used throughout the trial. All treatments were applied on 4, 14, 19 and 25 May and 2, 10 Jun using a CO2-powered backpack sprayer calibrated on 3 May @ 205.2 liters per acre. The sprayer was equipped with two TX-26 (hollow cone) spray nozzles spaced 46 cm apart and directed inward towards the base of the plants. On each sample date, five randomly selected plants per plot were sampled for CL, DBM and other lepidopterous larvae. Larvae were categorized as small (CL: instar 1 or 2; DBM—instar 1, 2 or 3) or large (CL—instar 3 or 4; DBM—instar 4, 5 or 6). All heads were harvested on 2 Jul and evaluated for insect feeding damage according to the following scale: 1 = no wrapper leaf damage, no head damage, 2 = wrapper leaf damage, no head damage, 3 = light head damage (3 or less feeding holes), 4 = moderate/severe head damage (>3 feeding holes). Heads rated 1 or 2 were considered marketable in accordance with USDA market standards.