Expert panel offers solutions to weed resistance issues

With the incidence of herbicide resistant weeds becoming more widespread, farmers are looking for answers to resolve existing challenges or avoid potential crop catastrophies. A panel of thought leaders at the 2012 Ag Issues Forum, hosted by Bayer CropScience prior to the Commodity Classic, addressed the issue and provided potential solutions.

According to the International Survey of Herbicide Resistant Weeds, there are 139 different types of resistant weeds in the United States. The overriding message of the expert panel was clear – weed resistance is spreading rapidly and has farmers searching for solutions.

Dr. Larry Steckel, Associate Professor, Plant Science, University of Tennessee, says the first instance of palmer amaranth in Tenessee soybean fields happened in 2001. "We’ve identified nine weed varieties resistant to glyphosate in the last 10 years, so if you look at that scorecard, we’re failing,” says Dr. Steckel.

"Farmers should get back to managing weed populations, not controlling them,” says Dr. Aaron Hager, Associate Professor of Weed Science at the University of Illinois. “The challenge becomes managing a weed population where there might not be any post emergence herbicide options for its control.”

A proactive approach to weed management is critical. A rotation of pre-emergence herbicides is the best option. The issue comes when there’s little moisture to activate the herbicide, and farmers need to turn to post-emergence alternatives, of which there are few options.

"Palmer amaranth can grow as much as two inches in 24 hours,” says Dr. Steckel. “If farmers can get in with an herbicide before it gets to 3 inches, it works about 95 percent of the time. If they wait until the next day and that plant is 5 or 6 inches, it’s too late.” Weed control comes down to a matter of logistics and getting into fields in time.

The Cost of Weed Resistance

Additional herbicide applications, more trips across the field with mechanical weed control, or complete replanting adds significant expense at a time when input costs are already high. Andrew Wargo III, Business Agent with Baxter Land Company in Watson, Ark., offered insight into government cost-share opportunities.

"There are numerous cost-share programs, land retirement programs or conservation easement programs available to help offset the costs of additional inputs or lost revenue from crop loss,” says Wargo. “These programs continue to be in high demand and are very cost effective.”

Dr. Steckel noted that as farmers lose acres decimated with resistant weeds, more operators are tilling up highly erodible land that in the past would have been placed under a government conservation program. In 2011 the National Resources Conservation Service (NRCS) began a program to offer financial assistance to those farmers that had weed resistance pressures but maintained conservation stewardship. More information on the program can be found at the NRCS website.

NRCS will pay for at least 75 percent of the costs of hiring technical assistance to develop conservation activity plans that outline weed management programs. Assistance is also available to offset some of the added costs or reduced income from managing weed resistance issues in order to preserve conservation practices on the farm.

The Respect the RotationTM program, initiated by Bayer CropScience in 2010, has helped offer solutions to weed resistance issues by encouraging the rotation of crops, traits and herbicides for a successful weed management program.