Caterpillar Control in Cabbages, Summer 1995

Cabbages were transplanted on 19 Oct 94 into a red krasnozem soil at the Redlands Horticultural Station, Cleveland, Queensland. Plants were spaced 0.3m in the rows, with rows 1.1m apart. Plots comprised 8 rows, 1.8m long separated by a 0.6m guard of bare ground in each row. Six treatments plus an unsprayed control, were arranged in RCB with four replicates. Regent 800WG 12.5, 25, 50, 100 gAI/ha, Hallmark 50 EC 17.5 gAI/ha and Dipel Forte 16 X 109 IU/ha were the treatments used. Five plants were randomly harvested from each plot and examined for the presence of larvae on 14, 21, 28 Nov 6, 12, 19 Dec 94. Insecticides were applied with an Echo® motorized backpack sprayer delivering 800 kPa through two hollow cone nozzles (Albuz® yellow 212) spaced 200 mm apart horizontally and calibrated to 400L/ ha on 15 Nov and recalibrated to 600L/ha on 7 Dec. Insecticides were applied on 15, 22, 29 Nov, 7, 13, 20, 28 Dec 94, 4 Jan 95. At harvest, 15 plants were rated for caterpillar damage as l=no damage, 2=1-2 holes, 3=3-10 holes, confined to packing leaves. 4=>3 holes, extending to surface of head. 5 = >3 holes, extending into paler leaves of the head. Ratings 1 to 3 were considered marketable.