Chemical Control of Southern Corn Rootworm on Peanuts, Emporia, Virginia, 1976

Peanuts, 'VA 61R', planted May 21'76 received granular insecticide and foliar spray applications on August 4. A second test with delayed timing received both types of applications on August 18. All plots received an in-furrow application of Disyston 15G at 1.0 lb a.i./acre for tobacco thrips control. Plots were 4 rows (36-in spacing) by 20 ft length with 5 ft alleys between 4 replications in randomized blocks. Soil was a Norfolk loamy fine sand with a pH of 6.2. Granular insecticides were applied as 14-in bands with pre-calibrated, tractor-mounted EzeeFlow granular applicators driven by an electric motor. Sprays were applied as 18-inch bands over the foliage with a CO2 pressure-regulated knapsack sprayer, calibrated to deliver 30 gal/acre with 3 nozzles/row at 75 psi. Plots of the first application date test received a shallow cultivation after the granular application to achieve soil incorporation. No cultivation was accomplished after the second (August 18) application date, due to excess vine growth and advanced fruiting (pegging). Insect damage evaluations were made September 20 to 24, 1976 by hand-digging 4 randomly selected plants from the 2 center rows of each plot. Mature and immature peanuts were pulled from the composite sample, washed and evaluated for rootworm injury. Pods were separated into categories of mature and immature as an aid in evaluating residual efficacy of the chemicals.