Apple, Dogwood Borer Control, Valatie, New York, 1982-83

A 9-yr-old apple planting of five cultivars, spaced 10 by 19 ft (230 trees/acre), 6 ft in height, on the M26 rootstock, was divided into 3 block. Block A contained three treatments and an untreated check arranged in a randomized complete block design with 10 tree plots replicated once on the ‘Mutsu’ and ‘Macoun’ cultivar and twice on the ‘Empire’ cultivar. Block B consisted of four tree plots of ‘Red Delicious’ cultivar with four treatments and a check replicated four times in a randomized complete block design. Block C was arranged in a similar design using 10 tree plots replicated five times with the cultivars Red Delicious and the other plots replicated five times with the cultivars Red Delicious and the other half Mcintosh. Treatments were applied 21 Jul. (Block A) and 5 Aug. (Blocks B and C in 1982, using a Spartan handgun sprayer at 150 lb/in2. Approximately 0.33 gallon of spray was applied dilute to runoff around the trunk of each tree from base to first scaffold level. Treatments were reapplied to the same plots on 15 Aug., 1983 using a Bean handgun sprayer at 200 lb/in2 delivering 0.5 gal of spray per tree. Rates and formulations were readjusted and the Tree-hold treatments omitted in 1983. All treatments were evaluated 2 Nov. 1983 by examining each tree for presence of live borer larvae, pupal skin, cocoons and fresh borer frass. Numbers of burr knots, i.e. above-ground adventitious root growths, were also recorded since borers usually became established at these sites.