ABSTRACT

Lintplus (dimethipin) plant growth regulator was applied to cotton at 30% open bolls in large field demonstrations in the mid-south and southeast in 2003 to evaluate its impact on harvest timing, yield and lint quality, especially micronaire. Targeted fields were with growers that normally would make two defoliation applications and cotton varieties which trend to high micronaire. Treatments were applied insplit plot trials on varieties in TX, LA, AR, MS, AL, & GA. Harvest timing data was obtained from 12 trials, with 7 of them indicating earlier harvest after Lintplus applications ranging from 2 – 3 days to 23 days with an average of 9.5 days. With the excellent conditions for defoliation in the 2003 season, Lintplus showed varying degrees of activity on defoliation 7 – 14 days after application. At 5-10 DAT (Days After Treatment), defoliation ranged from 20 – 80%. Yield differences between Lintplus and non-Lintplus (grower standard) treated fields ranged from -6.1% to +2.6% of yield except for one trial that had an increase of 297 lb/A yield, or +39.7% over the grower standard, in the Lintplus treated plot. This MS location was applied to evaluate Lintplus as an aid in reducing a boll rot problem, and the final results were very positive. Overall, yield data from these trials showed no negative impact from Lintplus applications. Evaluation of Lintplus effects on micronaire were mixed with approximately 50% of the field locations showing reductions in micronaire, between 0.1 and 0.6 units. These demonstrations support past research and field use data that Lintplus can help growers schedule harvest , potentially reduce boll rot and micronaire depending on variety and crop conditions.