Herbicide planning is critical for protecting crops and maximizing yields. Preventing weeds while preserving herbicide and trait technology requires strategically thinking through several factors, including weed biology, chemistry combinations and environmental impact. The Ohio Soybean Council recently chatted with Mark Loux, a professor in the department of horticulture and crop science at The Ohio State University (OSU) who has devoted his career to studying weeds. He shared insights to help farmers enhance their herbicide plans for the growing season.


Q: What are the main weed challenges Ohio growers need to watch for this year?

A: Waterhemp is on the verge of exploding here so that is our main focus right now. We’re trying to explain to growers what it means when a plant can produce upwards of a million seeds, how fast that can impact their fields and the type of herbicide required based on current resistance issues and its biology. Our main message is keep this weed and Palmer amaranth out of your operation. Extra effort to prevent them will pay off with regard to profitability and general lack of headaches.


Q: How has dicamba’s off-target injury changed herbicide planning in Ohio?

A: There appeared to be expectations before issues arose that farmers could use dicamba for post-emergence everywhere to take care of some herbicide resistant weed issues. Some still are, but many dealer groups and farmers won’t use it all or only on fields that are fairly isolated. Planting Xtend® soybean seed is one defensive strategy that works, but it’s not fair to the ag community as a whole or competing seed companies that something like this needs to be implemented.


Q: How can farmers develop a herbicide plan that provides integrated protection?

A: Start by making sure the program fits the biology of the weed, and take extra steps to prevent escapes from going to seed. Ideally, farmers use different herbicide chemistries for their corn and soybeans, mixing multiple modes of action in both pre and post emergence.

Not overusing the same seed traits and post-emergence herbicides in soybeans is especially key. The Enlist® trait just received final approval, offering growers the ability to use two post emergence herbicides – 2,4-D and glufosinate – that still work on resistant weed problems. This should reduce the risk of resistance compared with only using one. It really isn’t possible with other traits or non-GMO soybeans.

Planting cover crops – primarily cereal rye – can also help reduce weed populations. Fewer weeds popping up should help slow the rate of resistance development.


Q: What resources do you recommend for farmers looking to enhance their herbicide strategies?

A: Farmers should get their hands on one of the OSU weed science folders we give out at meetings every winter, which is sponsored by the soybean checkoff. They can also view the Field Leader event calendar for upcoming meetings and find more helpful information using these online resources:

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