Apple, Leafroller Control, 1977

Four different experiments were run simultaneously in the Brumback Experimental Block, Winchester, VA. Experiment No. 1 was designed to compare the effectiveness of various commercial formulations of Bacillusthuringiensis (Dipel, Thuricide HPSC, Thuricide HPC 1976 material, Thuricide HPC 1977 material). Experiment No. 2 compares the efficacy of materials already registered to control other orchard pests. Experiment No. 3 provides an in-depth look at one B. t. formulation (Dipel) in combination with other compounds, currently used in orchards, in an attempt to determine if the efficacy of the B. t. would be enhanced Experiment No. 4 compares the effectiveness of synthetic pyrethroids (SD 43775, Ambush 2E) to standard orchard insecticides. The experi-ments were laid out as a randomized complete block with single-tree plots replicated 5 times using 1 Winesap, 2 York, and 2 Rome trees. Trees were sprayed to runoff with the experimental materials using a Bean high pressure sprayer (35 gal/min pump) operating at 540 psi on the following dates: 28 June; 13 July; 11 and 25 August. Cover sprays (100 gal/acre cone) included: 29 March, Polyram; 7 April, Captan + Topsin M + Systox; 15, 26 April and 6, 20 May and 1 June, Captan + Topsin M; 6 May and 20 June, Phosphamidon; 14, 27 June and 11, 26 July and 10 August, Dikar; 26 August, Captan + Topsin M. Efficacy was determined by summer leafroll examinations, midseason and harvest apple evaluations. Leafroll counts were made by examining each tree for 15 minutes on 2-3 August. On 5 August, each treatment was evaluated by examining 250 apples (50/tree) for leafroller damage. Harvest evaluation of damage was made by exam-ining 500 apples (100/tree).