Soil Treatment with Systemic Insecticide for Control of Green Peach Aphids and Colorado Potato Beetles, Test 2, 1978

Abstract

Abstract On Mar 30, 'Russet Burbank' potatoes seed pieces were planted at Yakima in open furrows in Ritzville silt loam soil (Mesic Calciorthidic Haploxerolls) with a pH of 6.2 and 1.6% organic matter. For the planting time (PT) application the granular insecticides were dribbled through a hand-held, funnel-type applicator into the furrow over the potato seed pieces and the seed pieces covered. On May 15, when about 75% of these plants had emerged, similar plants in another set of plots were side-dressed (SD) with granular insecticides in 1-inch (2.5 cm) bands, 4 inches (10.0 cm) to each side at approximate depth of seed with a tractor-mounted Gandy applicator. In another set of plots, granular insecticides were applied over the tops of the small plants (Top) in a 10-12 inch (25.4- 30.5 cm) wide band with a tractor-mounted Gandy applicator and the granules then mixed with the soil by using a Lllliston cultivator. Each plot was 2 rows wide, (5.6 ft or 1.7 m) and 50 ft (15.2 m) long and each treatment was replicated 4 times in a randomized complete block design. The crop was sprinklerirrigated. The number of green peach aphids (GPA) on 20 compound potato leaves/plot was counted on May 30, Jun 8 and 20, and Jul 10. Colorado potato beetle (CPB) feeding damage, was evaluated by estimating the percent of plants damaged on Jun 12 and Jul 7. Also, on Jul 7, the number of CPB adults and larvae on 2 m2 of plant foliage (2 m long × 1 m wide between rows) and the number of dead adults and larvae on 2 m2 of soil between the rows were counted. The percent of foliage in each plot consumed by beetles was estimated on Aug 7 and the percent of plants destroyed by CPB were recorded on Aug 22. The data means were tested with analysis at variance by using Duncan's MRT at the 5% level.