Potato Insect Control, 1991

Abstract

Abstract Potatoes were planted on 7 May in South Deerfield, Massachusetts. Fertilizer (900 lbs 10N:10P:10K/ acre) was banded into the furrow at planting. Soil type was a fine sandy loam with a pH of 5.6. Manzate (fungicide) was applied at 1 lb. Al/acre on 14, 21, and 28 Jun and 11 and 18 Jul. CPB densities prior to first application were 2.9 adults, 8.2 egg masses, 16.3 early instars and 0.8 late instars per plant on 10 Jun. Treatments were replicated 4 times in a randomized complete block design. Each plot consisted of two 30 ft. rows with a 6 ft. fallow area between plots. Treatments were applied with CO2-pressurized sprayers at 40 psi, delivering 70 gal/acre. Applications were made on 10, 17, and 24 Jun and 1 and 10 Jul. The first application of ECX9124EH was on 10 Jun followed by weekly applications of M-Trak. CPB population densities were determined by counting larvae on 10 whole stalks in each plot. To evaluate microbial insecticides M-Trak, M-One, Trident II, and Foil OF, larvae were counted and recorded as early instars (first and second) or late instars (third and fourth). The performance of these materials was evaluated primarily by comparing late instars, as it took 4-5 days for the dead larvae to drop from the plants and early instars could have hatched between the last spray and the following count. The control plots were 70% defoliated when they were plowed under on 3 Jul.