Evaluating Thrips Control in Peanuts using Percent Damage Leaflet Ratings, 1997

Abstract

Abstract At-plant, in-furrow applied insecticides were evaluated for tobacco thrips control at the Peanut Belt Research Station in Lewiston-Woodville. Variety NC-7 peanuts were planted on 36-inch rows on 7 May at approximately 100 lb seed/acre. Soil temperature was 70°F and the soil was moist. The humic matter was 0.6% and soil pH was 5.9. Soil series consisted of Rains + Goldsboro sandy loam. Prowl and Vernam were used for early-season weed control. Plots were 2 rows wide by 50 ft long and each plot was separated by two buffer rows. Plots were arranged in a RCB design with four replicates. Plot ends were separated by 5-ft barren strip. Peanuts were planted using a Cole planter and in-furrow treatments were placed in the furrow with seed using electric Gandy boxes. The in-furrow application of Orthene 97% was applied by mounting spray nozzles directly behind the seed tube and connecting these to a CO2 sprayer on the planter. The sprayer was operated at 40 psi delivering approx. 30 gpa using 8003 flat-fan nozzles. Treatment rates and application techniques are listed in table. Peanuts were managed under standard agronomic practices. Thrips control was evaluated by determining the abundance of damaged leaflets per plot on 3, 12, and 16 Jun. Twenty-five, newly opened leaflets per plot were randomly selected and examined for thrips damage. The number of damaged leaflets was recorded. Stand counts were taken on 16 Jun. Yield was determined by digging, drying, and weighing peanuts from both rows of each plot on 7 Nov. All data were transformed (square root ofx + 0.50) prior to ANOVA and DNMRT. Actual means are presented in table.