Insect Pest Control in Cabbage, 1996

Six insecticide treatments were tested at Michigan State University Entomology Research Farm, in East Lansing, MI, for their control of imported cabbageworm, cabbage looper, and diamondback moth. Seedlings were transplanted at 2-ft spacing in single-row plots, 15 ft long, on 18 Jul. There was a 6-ft untreated zone between two plots with an untreated row (3 ft spacing) on either side of a treated row. Treatments were replicated four times in a RCB design. Insecticides were applied using a CO2 backpack sprayer with a single boom and a hand-held nozzle (30 psi, 20 gal/A). Treatments were sprayed on 12 and 23 Aug, and 4 Sep. All insects on two randomly selected plants were counted in each plot on 7, 16 and 29 Aug and 10 Sep. The percent defoliation of outer leaves was assessed for each plot on 17 Sep, before the heads were harvested. These were then assigned a marketability rating: no damage, slight damage (outer leaves of the head only), or unmarketable (damage to head beyond the outer couple of leaves).