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Working together to beat resistance

Working together to beat resistance

Farmers may have a new and free tool to use in the battle against herbicide resistance

By Kate Ayers
Staff Writer

Producers can turn to cooperative weed management to prevent herbicide resistance in hard-to-kill weeds.

Farmers on neighbouring operations can collectively make decisions about how to manage herbicide-resistant weeds, a release from the University of Illinois (U of I) said on Monday.

This new tool is highly effective and all it costs is some neighbourly interaction.

“I think we’re at a point now where farmers are looking for new tools. This tool is free, but it requires that people talk to each other and work together as opposed to doing everything on their own,” Adam Davis, research ecologist with USDA’s Agricultural Research Service and adjunct professor at U of I, said in the release.  

Waterhemp, for example, poses problems for cash crop farmers. The weed has developed resistance to multiple modes of action. So, the research team tested the efficacy of farmer cooperation using a computer simulation of waterhemp resistance evolution.

Using past data and management practices, the team came up with a realistic representation of waterhemp’s herbicide resistance in 2015. The scientists then projected results 35 years into the future to see how resistance may change under different management and cooperation scenarios, the release said.

“The crux of the story is that, if you do good stuff and you aggregate it at larger spatial scales, it gets even better. If you do bad stuff and you aggregate it at large spatial scales, it gets even worse,” Davis said in the release.

The “bad stuff” is using one mode of action every year, according to the simulation. This issue of chemical resistance was compounded when everyone applied the same product repeatedly.

However, if farmers used tank mixes with multiple modes of action, the spread and evolution of resistance was delayed. In fact, the delay was prolonged with increasing levels of cooperation, the release said.

“The message is not to use the most expensive herbicide program possible; the message is to use the available tools to manage your weeds better,” Davis said in the release.

“If you do that on your own farm, certainly it’s going to help. If you do it on a bunch of adjoining farms, it’s going to help even more. You can buy a couple decades at a time, in terms of delaying herbicide resistance, by aggregating the best practices at large spatial scales.”

Although the simulation looked at weed management cooperatives made up of 10 neighbouring farms, Davis said the number of producers working together isn’t as important as the spatial scale their operations cover.

He suggested forming weed management areas at the township scale and above, the release said.

This cooperation could be modelled along the lines of commodity groups and ag organizations.

Davis also suggested that the weed management cooperatives involve custom applicators in decision making, because they service many farms in a region, the release said.

The researchers are expanding their simulation to include such non-chemical control options as cover crops, crop rotation and the Harrington Seed Destructor. The team wants to see the potential benefits to using such strategies on larger scales.

They are also examining how much non-compliance a cooperative weed management system can withstand before the method will no longer work, the release said.

The full study is published in June issue of the journal Pest Management Science.  

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