Weed Management with Residual Herbicides and EngeniaTM in Bollgard II XtendFlexTM Cotton.

Engenia™ is a novel dicamba formulation under development by BASF for use in Bollgard II XtendFlex™ cotton which has the potential to improve control of a wide range of annual and perennial weeds. Resistant Palmer amaranth (Amaranthus palmeri), ivyleaf morningglory (Iponoea hederacea), Russian thistle (Salsola iberica), kochia (Kochia scoparia), field bindweed (Convolvulus arvensis), woollyleaf bursage (Ambrosia grayi), and Texas blueweed (Helianthus ciliaris) could be more effectively controlled with Engenia™ applied postemergence (POST) compared to Roundup PowerMAX^® (RUPM) applied alone. Field studies were conducted in 2013 and 2014 at Lubbock, Seagraves, and Halfway, Texas to evaluate Palmer amaranth, devil's claw, and Russian thistle control with Engenia™ and residual herbicides including Prowl^® H₂O and Outlook^®.

The objectives of these studies were to evaluate control of Palmer amaranth, Russian thistle, and devil's-claw with Engenia™ applied pre- or postemergence in Bollgard II XtendFlex™ cotton. Efficacy of Prowl^® H₂O applied preplant incorporated (PPI) or preemergence (PRE) and Outlook^® (POST) with Engenia™ for residual weed control was determined. 

Field trials conducted at the three locations compared Prowl^® and Prowl^® + Engenia™ (PRE) followed by RUPM alone, RUPM + Engenia™ or RUPM + Engenia™ + Outlook^® mid-postemergence (MPOST). POST only treatments include RUPM + Outlook^®, RUPM + Outlook^® + Engenia™, RUPM + Engenia™, or RUPM only. Treatments were applied using a backpack sprayer and applied at a rate of 15 gallons per acre. Weed control was estimated visually 17-21 and 60 days after planting at each location. Results from these trials over two years will be presented. Results from the 2013 studies demonstrated the continued need for residual herbicides when Engenia™ + RUPM are applied POST to Bollgard II XtendFlex™ cotton.