Irish Potato, Control of Potato Infesting Aphids, 1976

Experiments A, B, C, D, E, and F were 7 × 6, 4 × 6, 6 × 6, 5 × 6, 7 × 6 , and 6 × 6 randomized complete block designs respectively and were conducted at Presque Isle, Maine on land that was sown to oats in 1975. The planting date was June 4, 1976 for all experiments. In each experiment the 9.1 m space between blocks and the 1.4 m space between columns and at the sides and ends of the experiments were sown to oats at planting. Each plot consisted of 4 rows of potatoes 0.9 m apart and 15.2 m long. The 57 g healthy seed pieces were hand planted 30.5 cm apart. Fertilization and hilling practices were normal for the area. Late blight control was effected by weekly foliar applications of Rohm & Haas M 45 (2242 g ai/ha July 10 through August 31, 1976). Soil applications of insecticides were made by hand with a plastic tube applying previously weighed amounts of insecticide into the furrow just prior to planting. Foliar insecticide treatments were made with a Slosser sprayer (14.1 kg/cm2 and 1.2kl/ha) in combination with the fungicide. Numbers of aphids (by species) were counted on a top, middle, and bottom leaf of 25 plants in the 2 middle rows of each plot. When date of count and application are the same, aphid counts were made prior to application of the insecticide. Analyses of variance were calculated following transformation of the raw data using log10,(x + 1)- Means of the total number of wingless aphids were compared using Duncan's new multiple range test and then reconverted as given in the Table. The soil was classified as Caribou Loam, pH 5.2. Rainfall for June, July, and August was 112, 140, and 174 percent of normal. Temperature for the same 3 months departed + 3.5°, + 1.0°, and 0.0°C from normal.