Southern Corn Rootworm Control in Peanuts, North Carolina, 1991

Abstract

Abstract Peanuts were planted 9 May at the Bill Whitehurst farm in Pitt Co. Soil temperature was 66°F and seeding rate was approx. 90 lb/acre in an Exum A fine sandy loam with 0.8% humic matter and a pH of 5.5. Plots were 4 rows (on 36 inches center) × 20 ft with 4 replications/treatment arranged in a randomized complete block. The pre-plant incorporated (PPI) Lorsban 4 E was applied just prior to planting by spraying a broadcast treatment over the plot with a CO2-pressurized backpack sprayer using 8002 nozzles and operating at 40 psi. Immediately after application, the insecticide was lightly incorporated with a hand rake. The pegging-time applications of Lorsban 4 E were applied in a similar fashion, but were placed in a 16 inch band over the row and were not incorporated. A bicycle-wheel applicator utilizing a Noble metering unit was used to apply the at-pegging treatments on 16 Jul in a 16 inch band. Crowing conditions were dry in May and Jun, but Jul and Aug had above normal precipitation. This same wet weather also promoted increased leaching of pesticides. Peanuts were sampled for rootworm damage on 7 Sep by collecting 100 pods/plot at random from 5 plants in the 2 right-hand rows. Pods were placed in plastic bags and returned to the laboratory for freezing and subsequent examination. Peanuts were harvested 1 Nov, and yield was determined by harvesting the 2 left-hand rows of the plots. Data were subjected to analysis of variance and means separated by DNMRT. All data were transformed Vx = 0.05 prior to analysis, but actual means are reported.