Efficacy of Recovery Sprays to Synthetic Auxin Injured Cotton and Comparison of Multiple and Single Pass Harvest Systems Effect on Cotton Yield and Fiber Quality

The latest major technology advancement for cotton producers (Gossypium sp.) is arguably auxin-resistant cultivars, but this technology has created issues with auxin injury from off-site movement, requiring the use of coarse nozzles for herbicide application. To address these issues, studies were conducted to address defoliation with coarse nozzle tips and the ability to promote recovery of cotton plants from auxin injury. The study of nozzle types and carrier volumes revealed higher carrier volumes are more successful at defoliating and opening bolls than lower carrier volumes. Water volumes of 47 L ha-1 should be avoided when making cotton harvest aid applications, as all defoliation, open boll, and regrowth values were consistently reduced at the lowest carrier volume. Various nozzle types had less impact on harvest aid efficacy than carrier volume. In 2017, three recovery products (mepiquat chloride, N-Demand + Advantigro, and Radiate) used on dicamba-injured cotton resulted in similar yields to untreated cotton. These findings were not present for 2018 or 2019, as none of the recovery treatments produced yields comparable to the untreated check. For all three years of the 2,4-D trial, all the recovery treatments were comparable in yield and none of treatments improved yields, although in 2017, the auxin-only treatment resulted in similar lint yields to the untreated check. Another major concern for cotton producers is seed cotton removal from fields due to weather delays. A study was conducted to measure the benefits of early removal of seed cotton through a multiple picking process compared to the traditional single-pass harvest method. Over the seven site-years, for both picker- and stripper-harvested varieties, similar trends were observed for both yield, fiber quality, and gross revenue. These results indicated that multiple harvests provided comparable value for short-season and mid-late season cotton varieties. For lint yields, this research indicated there is more benefit to timely harvest for cotton grown in high-yielding and picker-harvested environments than non-irrigated, low-yielding, and stripper-harvested cotton. Furthermore, multiple harvesting provides a significant value and provides an economic justification for robotic harvesting to be developed for the cotton industry