Apple Pandemis Control, Half-Inch Green Application, 1984

Abstract

Abstract Insecticides were evaluated for control of overwintered apple pandemis larvae. Five-year-old trees on a semi-dwarf rootstock were used in this test. Treatments were applied with a handgun sprayer at 400 psi to the point of drip simulating a dilute application of approximately 400 gal per acre. Four single-tree replicates, each separated by an unsprayed tree, were used per treatment in a randomized complete block design. Treatments were applied on 6 Apr at the one-half inch green stage of flower bud development. Temperature at application was 50°F with a light wind (<5 mph). Pre-treatment counts of 5 fruit buds per tree provided an indication of relative infestation level in the orchard. Post-treatment evaluation was made on 17 Apr at "pink" stage of flower bud development. All flower buds on each tree were examined. The total number of buds, buds with feeding injury, and buds with live larvae were recorded. A moderate population of apple pandemis was present in the test orchard with about 5% of fruiting buds infested or showing signs of injury. Twenty five-leaf samples were collected from each tree on 12 Jul and 16 Aug, returned to the laboratory, brushed, and the number of mites recorded. Data are presented as average mites per leaf for the 2 sample periods.