Evaluation of Thrips Densities in At-Planting Seed and Soil Treatments on Sharkey Clay, 1996

Abstract

Abstract Plots were replicated four times in a RCB design and were four rows wide (40 inch spacing ) X45 ft. Stoneville 474 cotton seed of the same seed lot was planted on a Sharkey clay soil on 6 May. The seeding rate was 4 seed/row ft. Cotton seed was planted with a John Deere 7100 series planter which was equipped with 10 inch seed cones mounted to replace the seed hoppers. Granular in-furrow treatments were applied with 8 inch belt cone applicators mounted to replace the standard granular applicators. In-furrow spray treatments were applied with a CO2 charged spray system through 25015 nozzles (1/row) mounted in front of the press wheels. The spray tips were turned to spray across the furrow and calibrated to deliver 5 gpa finished spray. Control of thrips was assessed by randomly selecting 5 plants per plot on 20, 24, 28, and 31 May and 5 and 9 Jun. Plant samples were processed by using whole plant washing procedures to remove insects. Major pest and/or secondary pest control was initiated in Jun and continued on an “as needed” basis through Aug. Percentage of open bolls was determined by counting all open and unopened bolls within a 3.0 m section of a center row on 17 Sep. Plots were harvested on 24 Sep and 8 Oct. These data were subjected to appropriate calculations to determine percent first harvest. All four rows were mechanically harvested using a John Deere spindle type picker. Yields were converted by lb seed cotton/acre.