Herbicides in New Grass and Legume Seedings

Jun 21, 2021

By Dwight Lingenfelter

Only a limited number of herbicides can be used in seedling forages. See below for additional details.

Herbicide selection for new forage grass and/or legume seedings are limited. Most herbicide labels (e.g., 2,4-D, dicamba, triclopyr) for grasses like orchardgrass, timothy, smooth bromegrass, etc. state that the grasses should be well established with at least 4-5 inches of growth and have a well-developed root system before application.

Some labels are more restrictive than this. The metsulfuron label states that grasses should be established for at least 6 months prior to an application to ensure that they can tolerate potential stress from the herbicide. Herbicide selection, formulation (ester vs. amine) rate, and environmental conditions at application will all impact the potential for injury. Herbicide use in new legume seedings has similar concerns. In general, legumes should have several trifoliate leaves and be 2 to 3 inches tall before making an application. The Pursuit and Raptor labels state that alfalfa should have 2 trifoliates or larger at application; two of the most lenient products for new alfalfa seedings.

Also, keep in mind that, although we want the crop to have sufficient growth, the targets are generally "small" annual weeds which are easier to kill – a bit of a paradox. Products are even more limited with mixed seedings. Pursuit is labeled for established alfalfa-grass mixtures, as is metribuzin (Dimetric, MetriCor, etc.); MCPA (0.5 pints/A) has a label for use in seedling mixed stands of alfalfa, clover, trefoil with small grain or forage grass companion seedings. Butyrac (2,4-DB) and Maestro are technically not labeled for use in legume-grass seedling mixes. Maestro is labeled on legume-small grain companion seedings, and several other products have labels for CREP. Prowl H2O and Satellite HydroCap have supplemental labels for use in cool- and warm-season forage grasses to control certain annual grasses and broadleaf weeds.

Keep in mind, active ingredient only controls weeds before they emerge. If weeds have already emerged an effective foliar herbicide will need to be tank-mixed with Prowl H2O or Satellite. There are no herbicides labeled to control existing weedy grasses in grass hay or alfalfa/grass mixes, let alone in the forage seedling stage. However, Facet L (quinclorac) can be used in established cool-season grass systems (pastures or hay) to control/suppress certain grassy weeds (large crabgrass, foxtails, barnyardgrass, but not Japanese stiltgrass) that are less than 2 inches tall. Acclaim Extra, which can be applied in turf settings, is not labeled for use in forage grasses.

Source : psu.edu

Video: The 15-Year Bet Behind Every New Variety!

Canada is trying to decide how much agricultural research capacity it can afford to lose. Brian Rossnagel believes the better question is whether the country can afford to rebuild it.

The longtime barley and oat breeder makes the case with a simple fact about his profession: the consequences of today’s decisions may not become visible for 10 or 15 years.

“Pick the right parents. That’s the biggest thing,” Rossnagel says. “If you pick the wrong parents, you’re not going to get anywhere—and you don’t know that until 10 years, 15 years later.”

That warning carries particular weight as Agriculture and Agri-Food Canada moves to reduce spending and streamline parts of its science operations. The department’s 2026–27 plan anticipates the loss of approximately 665 positions by 2028–29 and says some research will be reduced where capacity exists in academia or industry. AAFC says the changes will make its science operations more cost-effective over the long term.

For Canada’s seed industry, Rossnagel’s career illustrates what is at stake.

This fall, the retired University of Saskatchewan breeder will be inducted into the Canadian Agricultural Hall of Fame. During his 35-year career at the Crop Development Centre, he helped develop more than 100 barley and oat varieties, including CDC Austenson—one of Western Canada’s most widely grown feed barleys. His induction recognizes not only those varieties, but the collaboration and research system that made them possible.

Rossnagel is quick to emphasize that none of it was the work of one person.

“The first thing I thought about was all the other people who contributed to whatever success I and my program had over the years,” he says. “We know that it’s not an individual who does this. It’s a group—a team.”

That team extends well beyond the breeder whose name appears beside a variety. It includes technicians, pathologists, quality specialists, statisticians, regional testing sites, seed growers and industry partners. It also includes the breeders who came before and those who will carry the germplasm forward.

CDC Fraser barley, for example, moved through three breeding careers. Its parents came from Brian Harvey’s program. Rossnagel advanced the material after Harvey retired, and Aaron Beattie later guided it through registration and release.

That kind of handoff is normal in plant breeding. The person who makes the original cross may never see the resulting variety reach farmers.

It also explains why lost research capacity cannot simply be switched back on when budgets improve.

“If you shut it off, it’s very, very difficult—and particularly costly—to start it up again,” Rossnagel says. “If you have to start from scratch, it’s going to be at least 10 years before anybody notices whether you’re getting anything done or not.”

The concern is not simply how many experimental lines Canada can process. Modern equipment, statistical tools and genetic technologies allow today’s breeding programs to evaluate tens of thousands of lines—far more than Rossnagel could handle when he entered the field in the early 1970s.

But efficiency and automation do not generate every idea.

“If you pare back down, and instead of having six or seven individual scientists concentrating on wheat breeding, you go down and say three people could handle all this, well, that’s half the ideas gone,” he says. “Particularly if you happen to lose the three people who had the really neat and innovative ideas, boy, that’s a problem.”

It is a timely distinction for Canadian agriculture. Consolidating programs may preserve the volume of material moving through a system, at least initially. It may not preserve the diversity of thinking, regional knowledge or willingness to pursue unconventional crosses.

That regional knowledge matters because Canadian agriculture is not one uniform production environment. A variety suited to southern Alberta may face different disease, moisture and maturity pressures than one grown in Manitoba, Ontario or Atlantic Canada.

“Agriculture is applied biology,” Rossnagel says. “Biology, all around the Earth, moves from the poles to the equator. It does not move from Newfoundland to B.C. like politics do.”