Cabbage Looper Control on Collards, 1981

This test was conducted at the North Alabama Horticulture Substation, Cullman, AL. Col lard transplants were planted on Jul 27, in plots consisting of 6 rows (44 inch centers and 18 inch spacing in the rows) x 25 ft separated by 5 ft alleys. A randomized complete block design with 4 replications was utilized. Treatments were applied on Aug 13, 20, 27, Sep 2, 9, and 16, with the exception of the 4 treatments containing viruses (SAN-404 and SAN-405 contain nuclear polyhedrosis viruses of Autographacalifornica [Speyer] and Trichoplusiani [HubnerU respectively), which were omitted on Sep 9 because of unavailability. Applications were made with a Super Blue Boy 600 high clearance sprayer operating at 250 psi and delivering 90 gal/acre through 3 TX26 nozzles/row. Larval counts were made on Sep 2 and 23. On Sep 2, counts were made of small, medium, and large T. ni larvae on 3 plants from the center 2 rows of each plot; on Sep 23, similar counts were made on 3 leaves from each of 10 plants/plot using leaves from the 2nd whorl from the top of the plant. On Sep 2, 16, and 23, plant damage ratings were taken for 20 plants randomly selected from the center 4 rows of each plot. Plants were rated on a 1-6 leaf loss scale, where 1 = 0-1%, 2 = 2-5%, 3 = 6-10%, 4 = 11-20%, 5 = 21-50%, and 6 = t50% loss. For analysis, damage ratings were converted to mean % damage for each rating class. Insect counts and damage ratings were subjected to analysis of variance, and means were compared by Duncan’s multiple range test.