Dicamba-resistant soybeans could provide producers an effective tool in battling glyphosate-resistant weeds.

Bill Johnson, professor of weed science at Purdue University, used field tests from 14 locations in 10 states to evaluate dicamba’s effectiveness on broadleaf weeds before and after soybean planting.

The study showed that dicamba applied just before planting provided 97-percent control of common lambsquarter and horseweed three weeks after treatment, but was slightly less effective on smooth pigweed, giant ragweed, velvetleaf, palmer amaranth, waterhemp and morning glory.

 Dicamba postemergence treatments improved control of velvetleaf, smooth pigweed, morning glory and waterhemp. When combined with glyphosate, dicamba gave 30-percent to 65-percent better control over glyphosate-resistant palmer amaranth, waterhemp, horseweed and giant ragweed compared to glyphosate alone.

"This is a powerful postemergence herbicide that we can pair with glyphosate to kill glyphosate-resistant weeds," Johnson said.

Pending regulatory approval, producers can expect dicamba-resistant soybean products in 2013.