Efficacy of Selected Pyrethroids and Pyrethroid-Ov1Cide Combinations Against Bollworm and European Corn Borer in Southern North Carolina, 1989

Cotton was planted on 15 May in a Marlboro sandy loam soil in Laurinburg, NC. Recommended agronomic practices for fertility and weed control were followed and 0.6 lb (AI)/acre Temik used at planting for thrips. A randomized complete block design with 4 replicates and 6-row (40 inch centers) x 45 ft plots with 10 ft alleys were utilized. Treatments were applied with a backpack CO2-pressurized sprayer calibrated to deliver 8.0 gal/acre total volume at 50 psi with one TX-8 Spraying Systems® nozzle per row. Applications were made on 28 Jul, 4 and 7 Aug and 6 Sep. One hundred squares and bolls per treatment (25/plot) were inspected for damage and live ECB and BW larvae 72 h after the 2nd and 3rd applications. European corn borer main stem tunnels were counted on 100 plants per treatment (25/plot) on 31 Aug. A final 100-boll sample was taken on 22 Sep and inspected for ECB and BW damage. Yield were harvested from the middle 2 rows with a 1-row John Deere mechanical harvester.