Control of Lepidopterous Insects on Cabbage, 1996

Six-week-old field-grown cabbage transplants (cv. ‘Rio Verde’) were planted on 20 May at the Mountain Horticultural Crops Research Station (Fletcher, NC). Plots consisted of two 25-ft-long rows on 3.5 ft. centers, with 7 ft. of cultivated soil between treatment rows. Plants were spaced 12 in. within rows. Each treatment was replicated four times and arranged in a RCBD. Treatments consisted of an untreated control and approximately 7-d interval applications of the following materials (see table for rates): Asana XL, Baythroid, Karate, Able, Agree, Biobit, Dipel, Xentari; and unregistered materials TD-2344-02, Confirm, Spinosad, Proclaim and MYX 833. All materials were applied on 14 and 24 Jun, 1, 9, 18, and 25 Jul. Applications were made with a tractor-mounted PTO-sprayer delivering 50 gpa through 3 hollow cone nozzles per row (1 overhead and 2 drop nozzles). Latron B-1956 (0.06%) was added to the spray solution of all treatments. Lepidopterous larval populations were counted on 10 heads/treatment on 20 and 27 Jun and 3, 11, 17 and 24 Jul. Crop quality was assessed on 30 Jul, by rating 10 heads/treatment on a scale of 0-5 (0 = no damage, 1 = frame leaf damage, 2 = minimal wrapper leaf damage, 3 = significant wrapper leaf damage, 4 = some head damage, and 5 = severe head damage). All heads receiving a rating of ≤ were considered marketable. All data were analyzed using a two-way ANOVA, and means were separated by LSD (P = 0.05).