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

Six week old plants were transplanted into a Bernow series fine, sandy loam soil at the Wes Watkins AREC in Lane, OK. Plots measuring one row wide by 4.6 m long were arranged in a randomized complete block design with four replications. One unplanted bed between beds and 3 m within rows served as spray buffers. Beds were spaced 0.9 m apart and plants were spaced 30 cm apart and arranged with two rows on each bed. Conventional cultural practices were used throughout the trial. All treatments were applied on 14, 19 and 25 May and 2, 10, and 16 Jun using a COrpowered backpack sprayer calibrated on 3 May at 205 liters per acre at 30 psi. The spray boom was configured with two TX-26 hollow cone 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 from each plot were harvested on 21 Jun and rated for lepidopterous 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 feeding holes), 4 = moderate/severe head damage (>3 feeding holes). Heads rated 1 or 2 were considered marketable in accordance with USDA market standards.