Purdue Extension plant and weed experts have teamed up to author a new publication that offers information about controversial new herbicide-tolerant soybean varieties.Approval of 2,4-D- and dicamba-tolerant crops is pending, but many people, including some weed scientists and both agronomic and specialty crop growers, have concerns about spray drift. The publication, 2,4-D- and Dicamba-tolerant Crops – Some Facts to Consider, does not take a position on the crops; rather, it serves as an unbiased, research-based fact sheet.It is available for free download via Purdue Extension’s The Education Store at https://www.the-education-store.com/ by searching for item number ID-453-W. “It’s important to note that there is no unified opinion on this topic among weed scientists or agronomic crop growers,” said Bill Johnson, Purdue Extension weed scientist. “This publication shares the perspective of some Purdue University scientists on the subject of managing weeds in crops, explains why 2,4-D- and dicamba-tolerant crops were developed and why they are needed by some crop producers, and discusses some of the concerns surrounding the short- and long-term effects of this technology.”
Opponents of the herbicide-tolerant crops fear that the new technology is unnecessary, will make farmers more dependent on the intellectual property held by large corporations, will injure nontarget crops sensitive to 2,4-D and dicamba, and will accelerate herbicide resistance in weeds, Johnson said.
“Those in favor of the new soybean varieties argue that 2,4-D and dicamba have been used on millions of acres since the 1960s and have not resulted in widespread damage, so using them on tolerant crops should not concern growers of high-value horticulture crops, if the new low-volatility formulations are sprayed and applicators follow recommended stewardship guidelines to avoid off-site movement,” he said.
Johnson is one of the publication’s seven authors. Others are Steve Hallett, Purdue University associate professor of botany and plant pathology; Travis Legleiter, Purdue Extension weed scientist; Fred Whitford, coordinator of Purdue Pesticide Programs; Steve Weller, Purdue University professor of horticulture and courtesy professor of botany and plant pathology; Bruce Bordelon, Purdue Extension small-fruit specialist; and Rosie Lerner, Purdue Extension consumer horticulture specialist.
Topics reviewed are background on weed management and current problems, new weed management approaches, developments in herbicide-resistant crops, logic for this technology, concerns about off-site movement, factors affecting off-site movement, and methods of minimizing off-site movement.