Potato Insect Control, 1985

Abstract

Abstract Potatoes were planted on 9 May in So. Deerfield, MA. Fertilizer (700 lb. 10N:10P2O3:10K2O/acre) was broadcast and incorporated prior to planting. An additional 700 lb/acre was side dressed on 26 Jun. Soil type was a fine sandy loam with a pH of ca. 5.3. The land was rotated from corn and no other potato crops were planted within 0.5 miles. Hence, Colorado potato beetle (CPB) pressure was moderate. Treatment blocks were replicated 4 times in a randomized complete block design. Each plot consisted of two 30-ft rows with a 3-ft fallow area between each plot. Treatments were applied with C02 pressurized sprayers at 40 psi with a delivery rate of ca. 65 gal/acre. Applications were made on 3, 11 and 17 Jul. In one treatment, Alsystin 4F at 0.5 lb (AI)/acre was applied on 3 and 11 Jul, and on 17 Jul, Alsystin 4F at 0.25 lb (AI)/acre plus Monitor 4 at 0.5 lb (AI)/acre was applied. CPB densities were assessed on 3 Jul and 4-5 days after treatment by counting adults and larvae on 10 primary stalks in each plot. Green peach aphids (GPA) were sampled on 29 Jul by counting those found on 10 terminal leaflets from lower leaves. Predators were assessed on 29 Jul by counting individual larvae, pupae and adults per 10 stalks. Coleomegilla maculata was the dominant predator species. Because densities of individual species were not high, predator numbers were pooled. Each plot was rated for defoliation on a scale from 1 (0-20%) to 5 (80-100%). Potato leafhopper (PLH) damage was assessed by ranking damage from 1 (no damage) to 3 (severe). Due to their clumped distribution, CPB and GPA counts were transformed by log(x = 1); means reported here are back transformed. No effects from blocking were observed for CPB.