Systemic Insecticides for Control Of M. Persicae and L. Decemlineata on Potato, 1976

‘Russet Burbank’ potatoes were planted April 16 in Ritzville silt loam soil at Yakima, Washington. Plots were 2 rows wide, 34 inches (86 cm) apart and 50 ft (15.2 m) long. Each treatment was replicated three times in a randomized complete block design. On June 1, when about 75% of the plants had emerged, sidedress applications of granular materials were applied with tractor-mounted Gandy applicators. These granules were placed in 1-inch (2.54-cm) bands, 4 inches (10.2 cm) to each side and at about the same depth as the potato seed pieces. On the same date, topical applications of granular materials were made by using a funnel-type, hand-operated applicator. These granules were placed in 6-to 8-inch (15- to 20-cm) bands over the tops of the small potato plants and then mixed into the soil with a Lilisfon cultivator. The crop was sprinkler irrigated immediately following the treatments. Aphid populations were determined by collecting 20 compound potato leaves from the lower two-thirds of the plants from each plot on June 8, 18, July 8, and August 3. Visual ratings of the damage (0 = no damage and 10 = plants destroyed) done by the Colorado potato beetle were made in each plot on August 12, 19, 26, and September 2. The data were subjected to analysis of variance and Duncan’s multiple range test.