Field studies were conducted on a sandy loam soil in 1991 in Rillito, AZ to measure the response of cotton (Deltapine 20) and woolly morningglory to postemergence applications of DPX-PE350 50DF applied at 0.25, 0.50, 0.75, 1.0, 1.5 and 2.0 oz ai/A. All early postemergence treatments included 0.25% V/V of X-77 while early layby treatments included both X-77 and crop oil concentrate (I% V/V). DPX-PE350 applied over-the-top of 2 to 3 inch cotton or post-directed to cotton 12 to 18 inches tall resulted in minor injury to the foliage. Early postemergence and layby applications were applied using 8002 flat fan and K2.5 floodjet nozzles respectively which the applied spray solutions at a rate of 20 gallons per acre. Crop injury was (leaf speckling, chlorosis of expanded leaves) more noticeable on the taller cotton but in both instances the injury was considered minor and disappeared after an irrigation. when applied as an early postemergence treatment, DPX-PE350 at 0.75 oz/a controlled 84% of the morningglory that was in the cotyledon to 1st true leaf stage. Higher concentrations of DPX-PE350 (>1.0 oz/a) were necessary to control the larger woolly morningglory (2 to 10 leaves). Regrowth from taller morningglory treated with DPX-PE350 at rates below 1 cz/a was common. When DPX-PE350 was applied with X-77 as an early layby treatments morningglory control dropped below 80%. Replacing X-77 with crop oil concentrate improved morningglory control by 10%. Morningglory control dropped below 70% with all rates of DPX-PE350 by 56 days after treatment indicating DPX-PE350 is incapable of seasonlong control of woolly morningglory.

In summary DPX-PE350 applied at 1.0 oz/a or more provided better than 80% control (80% or better) of woolly morningglory with minimal cotton injury. Further research is needed to determine how DPX-PE350 herbicide may impact crops normally grown in rotation with cotton. Research should also be conducted to determine how soil moisture levels at the time of treatment affects crop and weed response to DPX-PE350.