Control of the Cabbage Looper and Imported Cabbageworm on Collards with Nuclear Polyhedrosis and Granulosis Viruses and Bacillus Thuringiensis, 1982

'Vates' collards were direct seeded in 3 row plots 20 ft long on Jul 8. Plants were spaced 4-6 inches apart in the row and 36 inches between rows. Each row was buffered by a guard row. The treatments were arranged in a randomized complete block design with 4 replications. The soil was a Norfolk 'A' loamy sand. All spray treatments were mixed in 0.5 liter of water and applied with a trombone type garden sprayer calibrated to deliver 30 gal/acre. Because the nuclear polyhedrosis viruses do not infest the imported cabbageworm, the granulosis virus was sprayed so that damage primarily from cabbage looper could be assessed. Treatments of the Pieris rapae granulosis virus were applied on Aug 10, 17, 24, 31 and Sep 7. Treatments of the nuclear polyhedrosis viruses, Bacillus thuringiensis, Lannate, and Pydrin were applied on Aug 17, 24, 31 and Sep 7. Foliage injury ratings ranged from 1-5 and were indexed as foI lows: (1) 0-3% damage = odd holes on leaves; (2) 4-10% damage = few leaves with holes; (3) 11-25% damage = moderate number of leaves with holes; (4) 26-50% damage = most leaves with holes; and (5) 51-100% damage = crown damage and/or all leaves with holes.