How to manage weeds in 2021 and beyond

Technology will make managing weeds easier, but optimum weed management also entails consideration of older technologies.

Weeds remain the eternal enemy that farmers faced in 2020 and will continue to face. Still, the digitization of agriculture will help farmers fight weeds and other pests in the future, says Howard Dahl, CEO of FarmQA, a Fargo, North Dakota, firm that develops digital tools for crop scouting.

“We have about 100 agronomists using our software right now,” he says. “Each year, we ask them what they need, and make improvements.

“I believe we will see a revolution in the ability to manage in real-time problems on the farm,” Dahl adds. “I think it will come from drones flying over fields with hyperspectral imaging cameras, identifying specific diseases and weeds for spot spraying.” After you do a map of the field, you can say, ‘I need to spray these weeds on this section of the field.’

“I also think we will see some real breakthroughs in combination of artificial intelligence,” he says. “Just as you do in a factory with ISO 9001 standards in managing nonconformance in real time. I think we will see the tools to make that possible. 

Preserve Current Herbicide Sites of Action

Prior to 2000, chemical companies churned out new herbicide sites of action. However, that’s no longer occurring. The last new herbicide site of action — the HPPD inhibitors (Group 27, chemistries like Callisto) — debuted around two decades ago. Since then, all “new” herbicides that companies have marketed are formulations and premixes of existing herbicide sites of action.

That makes proper use and application of all existing herbicide sites of action, including those herbicide formulations used in systems that tolerate glufosinate (Liberty), glyphosate (Roundup), 2,4-D choline (Enlist formulations), and dicamba (XtendiMax, Tavium, and Engenia). 

Mark Storr, BASF technical representative, points to a 2020 BASF test plot near Story City, Iowa, in which no damage resulted from three herbicide-tolerant systems — dicamba, 2,4-D, choline, and glufosinate — adjacent to each other. 

“We proved it can be done, but label directions need to be followed to steward these products properly,” he says. 

Cultural practices also need to be incorporated into future weed management systems, he says. 

“We have become very dependent on herbicides,” says Storr. “They have allowed us to substitute capital for labor. As farms have gotten larger, they haven’t cultivated as they used to, since they have a lot of acres to cover. That’s the way agriculture has taken us, whether that’s right or wrong. But it has made us more dependent on herbicides to where it’s a struggle to go back to some of the old established ways (of weed control) like cultivation and hand weeding. But we need to look at those things, along with herbicides.”

Optimum application timing is also crucial for weed control with herbicides, adds Storr. 

“A lot of times, pop-can height is used as a guideline to spray weeds,” he says. “But that is 6 inches high. We need to apply earlier, when weeds are 4 inches high or less.” 

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