Control of Collard Pests, 1988:

Abstract

Abstract ‘Vates’ collards were direct seeded in 4-row plots 20 ft long on 13 Jul. Plants were spaced 2 inches apart in the row with 36 inches between the rows. The treatments were arranged in a randomized complete block design with 4 replications, and each sprayed row was buffered by an unspraved guard row. The soil was a Norfolk A loamy sand. All spray treatments were mixed in 0.5 liter of water to which 0.01% of a liquid detergent was added as a spreader and applied with a trombone type garden sprayer calibrated to deliver 30 gal/acre. The Autographa californica nuclear polyhedrosis virus (NPV) was applied in an unencapsulated formulation and several encapsulated formulations with different sunscreen materials to determine the effectiveness of these materials in protecting the virus from the ultraviolet and visible light just above the UV region. The NPVs do not infect ICW so that damage to plants in rows treated with virus was from ICW and CL. All rows were treated with their respective applications on 16 and 23 Aug. On 23 Aug 50 second-instar CL were released on each of the test rows. On 7 and 14 Sep the foliage injury ratings and insect counts were taken. Foliage ratings ranged from 1 to 5 and were indexed as follows; 1, 0-3% damage (odd holes in 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, all leaves with holes, or both).