Evaluation of Thrips Densities in At-Planting Seed and Soil Treatments on Gigger Silt Loam, 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 Gigger silt loam soil on 7 May. The seeding rate was 4 seed/row ft. Cotton seed was planted with a John Deere 7300 series planter which was equipped with 10 inch seed cones mounted to replace the seed hoppers. Granular in-furrow treatments were applied with 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 18 Sep. Plots were harvested on 26 Sep and 10 Oct. These data were subjected to appropriate calculations to determine percent first harvest. The center two rows were mechanically harvested using a John Deere spindle type picker. Yields were converted to lbs seed cotton/acre.