Apple, Test of Insecticides, 1978

Abstract

Abstract Experimental sprays were applied to runoff to single-tree plots in a randomized block design consisting of 4 replicates of Golden Delicious. Treated single trees were separated by others not sprayed with insecticides. Experimental sprays were applied with a John Bean sprayer, 35-gpm pump, equipped with a spray mast carrying 7 spray guns arranged to wet the uniformly trimmed trees. Approximately 8.0 gallons of spray was applied per replicate tree. Spray dates for the test insecticides were: May 30, Jun 15, 29, Jul 12, 26, Aug 9, 23, and Sep 6. During May, general sprays involving Cyprex, Polyram, sulfur, and calcium chloride were applide with an airblast sprayer at 50 gallons of water/acre to the whole experimental block. From June through July, the general sprays involved captan, sulfur, and calcium chloride. Late season general sprays were of captan and zineb. Average temperatures were: May 58.6°F, Jun 68.5°F, Jul 70.4°F, Aug 74.1°F, and Sep 64.8°F. Rainfall in inches averaged: May 5.67, Jun 3.24, Jul 7.98, Aug 2.46, and Sep 1.5. Effectiveness on the apple aphid was evaluated by counting the number of infested terminals/10 top terminals/tree, the number of aphid infested leaves/terminal, and the number of aphids/most infested leaf/infested terminal. The effect of the sprays on the white apple leafhopper was evaluated by counting the number of nymphs/25 leaves/tree. The effectiveness of the test materials on the the Japanese beetle was assessed by counting the number of damaged terminals/20 top terminals/tree and the number of damaged leaves/terminal. Effectiveness of the test chemicals on the European red mite, the two-spotted spider mite, and predatory mites was evaluated by counting the mites several times during the season on samples of 15 leaves/tree, 60 leaves/treatment. The effect of sprays of the predator S.punctum was evaluated by 3-min. counts of adults and larvae around the periphery of the test trees. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury all drops after Jun 27 and 2 picked samples on Aug 2] and Sep 20. Apple samples averaged 220 fruits/replicate and 880/treatment. Pest pressure was moderate throughout the season.