The re-registration of dicamba herbicide products (i.e., Xtendimax, Engenia) came with a new set of restrictions on application. The downwind buffer requirement for dicamba was increased to 240 feet. Although there is specialized application equipment (hooded sprayers) that can be used to reduce this buffer requirement, most growers prefer to use existing broadcast equipment. This proposed project will show South Carolina soybean growers effective herbicide programs that will work under the new label requirements. When applied at the correct timing, dicamba alone control Palmer amaranth and other troublesome broadleaf weeds. Relying solely on postemergence dicamba alone can lead to weed resistance concerns. There are documented cases in the United States of dicamba-resistant weeds. These herbicides program will minimize these concerns by incorporating other modes-of-action and soil residual herbicides in the management programs.

1. To evaluate selected dicamba based herbicide programs on troublesome weeds in soybean.
2. To disseminate these research results to South Carolina soybean growers through field days and grower meetings.

1) 4 Quarterly reports to the SC soybean board
2) 1 final report to the SC soybean board
3) Present soybean injury results to soybean growers at county and/or regional Extension soybean meetings January 1 through March 31, 2022.

Updated April 15, 2021:
The field site at the Edisto Research and Education Center has been selected, prepared, and the appropriate preplant fertilizers have been broadcast across the study area. Also, the soybean seed and herbicides have been acquired for this study. Soybean planting is planned during the first two weeks in May, depending on the weather conditions.

Updated July 15, 2021:
The field site at Edisto REC was planted on June 25, 2021. Due to excessive rain events in first half of June and the wetness of field site, planting was delayed. The soybean variety was Asgrow 69XFO. Plot measurements were 4 rows by 40 ft. Study was replicated 4 times. After planted, the preemergence herbicide Envive was sprayed at 4.0 oz/A across all plots except for untreated. The first postemergence application was on July 13, 2021. The efficacy of the Envive preemergence treatment was very effective (>95% control) of Palmer amaranth, annual morningglory, and Texas panicum. Very little crop injury was noted. More information to follow on the next postemergence treatment and efficacy weed ratings in the next progress report.

Updated October 15, 2021:
See file below for the 3rd quarter progress report.

View uploaded report

Updated December 15, 2021:
See file below for the 4th quarter progress report.

View uploaded report

Updated January 17, 2022:

View uploaded report

This project will deliver research-based information on effective dicamba herbicide systems that will increase grower’s knowledge to effectively manage troublesome weeds in soybean production.