Weed Control Project
Every winter, the North Central Research Extension Center, located south of Minot on U.S. Highway 83, takes samples of different weed seeds in the area and tests what chemicals are most effective to treat unwanted growth throughout the year.
This program started about 10 years ago when the greenhouse was constructed. The greenhouse is utilized to test different weed seed sources from around the Minot area for herbicide resistance. The seed sources are evaluated and categorized as either resistant, moderately resistant, slightly resistant or susceptible.
“The greenhouse has been an important tool for evaluating herbicide use in North Dakota,” research specialist Tiffany Walter said. “This research helps the grower or producer know what chemistries are still available to help control the weed sample.”
Field weed control studies are conducted in small grains, canola, sunflowers, flax, dry beans, peas, lentils, chickpeas, faba beans, corn, soybeans and other crops. They evaluate new herbicides/adjuvants or different uses of existing products in various crops.
They also look at the impact of different cultural practices, such as crop rotation and conventional tillage versus no-till, on crop yield, seed quality, weed control and economic feasibility.
Ultimately, the goal of the weed control project is to help farmers protect their crops from weeds and, hopefully, save money.
The research center has studies that target specific weeds, such as Canada thistle, wild oat, foxtails, kochia, narrowleaf hawksbeard, horseweed and many others. The research center takes requests from growers, co-ops and companies to test weed seeds for chemical resistances.
In their studies with wild oat, the research center looked at the response to group 1 and group 2 herbicides. The different groups determine how the herbicide acts on the weed.
In each field studied, the Select herbicide, from group 1, had killed almost every sample. Puma, also from group 1, showed that the wild oat was resistant.
Though the chemicals are from the same group, they have different chemistries. Walter says it is important to look at the chemistries, not just the trade name. Many growers and producers might think that because a product has a different name, it’s a different chemistry, which isn’t always the case.
For green foxtail, the herbicide Raptor, which is a group 2, was most effective in killing off the weed while Puma, a group 1 herbicide, was the least effective.
In recent years, glyphosate resistance issues have been rising in the state. Because of this, the research center does test for glyphosate resistance in kochia.
Glyphosate is an herbicide that is applied to the leaves of plants to kill both broadleaf plants and grasses, according to the National Pesticide Information Center. The NPIC says that glyphosate is one of the most widely used herbicides in the United States, which is why there is such an uproar in resistance to the chemical.
Kochia is a shallow germinating plant, which allows it to be competitive in dry, saline soils. Kochia is most commonly found in the Great Plains and is well-adapted to cultivated, dryland agriculture. With severe infestations and low crop competition, Kochia can cause 100 percent crop loss.
Currently in the greenhouse, the research specialists are looking at a kochia sample and were asked to treat with Dicamba and Talinor herbicides to see which chemistry would be better suited for the field.
In the kochia samples at the greenhouse, you could see the Dicamba was acting on the kochia, but the Talinor had completely killed the weed.
“The difference with herbicides is the timing on them. Some of them act a lot faster than others,” Walter said. “The different chemicals have a different timeline on how it kills (the weed).”
When testing, the research specialists will plant the weed seeds, and wait for them to grow. Once the plants have developed, the researchers will spray the plants with the different chemicals they are testing and will evaluate the effectiveness at 10 days and then again at 20 days.
When the center has plenty of seed sample, they will test the weeds against every chemistry they can to let the farmers know exactly what resistance has been built up for their fields’ weeds.
“Those are the things we look at, because if the grower wants to know one thing, sometimes they may have another issue they aren’t even aware of and sometimes we find out they’re better off than what they originally thought,” Walter said.
Walter says a key to keeping a product effective is rotating chemicals. Rotating between chemistries should help with longevity of a product.
For more information about the weed control program, visit the research center’s website at www.ag.ndsu.edu/NorthCentralREC, or give them a call at 857-7677.