Impact of Foliar Sprays on Green Peach Aphids and Ladybird Beetles, 1982

Abstract

Abstract Certified, Class B ‘Katahdin’ seed potatoes were planted on 4 May, with a 9-inch spacing between plants. A randomized complete block design with three replications was used. Treatment plots consisted of three 25-ft rows planted 34 inches apart. A 10-ft alleyway separated blocks. Temik 15 G (2.0 lb (AI)/acre) was applied in furrow at planting. Dithane M-45 was applied at 1.5 lb (AI)/acre on a 7-day schedule for potato late blight control. The foliar insecticides were applied 30 Jul., 13 Aug., 23 Aug., and 13 Sep. in 40 gal of water per acre at 62 lb/in2 with a 6-ft boom sprayer equipped with three TeeJet D2-25 disc-core cone nozzles per row. Tractor speed was 3 mph. Three leaves per plant, three plants per treatment plot (27 total leaves/treatment) were sampled weekly from 12 Jul. to 16 Sep. for green peach aphids. The number of ladybird beetle predators was counted on one stem per plant, three stems per treatment plot (nine total stems/treatment). A minimum of one row per treatment was harvested from each block on 5 Oct. and graded for size. Rainfall in inches totaled 3.07 May, 7.71 Jun., 4.11 Jul., 1.72 Aug., 2.80 Sep. Mean monthly temperatures (°F) were 61.5 May, 63.5 Jun., 71.1 Jul., 65.4 Aug., and 61.2 Sep.