Loyant herbicide could help with ‘big players’ in fight with weeds

Farmers are always looking for the next “silver bullet,” the herbicide that, like glyphosate in the 1990s and early 2000s, will control a wide range of problem broadleaf weeds and grasses at larger than seedling size.

The new Loyant herbicide with Rinskor Active that Dow AgroSciences hopes to register in rice in late 2017 or early 2018 may come close to that. Even so, Dow scientists are already cautioning growers not to think of it as a stand-alone herbicide or, well, a “silver bullet.”

“Currently, we have products that are very good on sedge, but they may miss some of the pertinent grasses,” says Hunter Perry, field research and development scientist with Dow AgroSciences. “They may be good on broadleaves and some sedges, but they don’t control grasses.”

Dr. Perry was one of a number of Dow AgroSciences researchers who spoke about a number of new products the company has launched or is planning to launch in coming months during the company’s Strongest in the Field Media Event at the Dow AgroSciences Diamond Showcase demonstration field near Leland, Miss.

“Loyant is going to bring broad spectrum control across those different types of weeds. To start with, Loyant controls the No. 1 grass in rice in the U.S., barnyardgrass. It controls very pertinent sedges, such as rice flatsedge and yellow nutsedge. It also controls smallflower umbrellasedge, which is beginning to pop up and become very problematic in several areas of the Mid-South.”

As for broadleaf weeds, Loyant is expected to control black-seeded weeds: hemp sesbania, jointvetch and numerous aquatic species, such as creeping water primrose, ducksalad, slender arrowleaf, arrowhead and others. 

Overlapping control of weeds

“We’re very excited because Loyant overlaps across many of these spectrums,” Dr. Perry said. “When you look at the most problematic and the most economically pertinent weeds in rice in the Mid-South, Loyant controls many of those species, so it’s very exciting for us.”

Loyant will be a valuable tool in the battle against herbicide-resistant broadleaf weeds and grasses in rice, he says.

.”We control the propanil-, the ALS- and the quinclorac-resistant barnyardgrass biotypes. ALS-resistant flatsedge is a big one that we keep hearing about. Many university scientists and consultants are telling growers to assume flatsedge is ALS-resistant.”

Loyant also is active on Palmer amaranth, which can be a problem when rice first emerges.

“That’s big for a grower in that early postemergence segment where they plant their rice, and they get their Command and glyphosate out, and before the rice is one-leaf you have Palmer amaranth germinating in the stand,” he said.

“Loyant will do a very good job of controlling both susceptible, glyphosate-resistant and ALS-resistant biotypes of Palmer amaranth in this situation,” he said while describing how Loyant works on a test plot that was sprayed after becoming infested with Palmer amaranth and barnyardgrass.

Tankmixes with other Dow herbicides

The Palmer amaranth was bent over and crinkled. Dr. Perry demonstrated how the stems had become brittle and could easily be broken off. The barnyardgrass was floating on the water’s surface and could be pulled out by hand.

“The first thing you will notice after you treat barnyardgrass is you’re going to see an immediate stoppage of growth,” he said. “You will see a slight yellowing within several days of application, and you will see nodes swelling at the base of the plant. If you just put your hand in the water and sweep it without putting any real pressure on, the barnyardgrass sluffs off at the crown of the plant.”

Although Loyant is a broad-spectrum herbicide, Dow AgroSciences will recommend growers use it in a full-season program when registration is received for the product possibly in late 2017 or early 2018.

“Anybody will tell you a full-season program is the way to go,” according to Dr. Perry. “If you don’t start with clean fields early, you will have weeds competing with your rice throughout the season. You’re going to see an immediate drop in yields when you have weeds early on in your rice.”

Each of the test plots received a pre-emergence application of Command followed by Ultra Blazer postemergence to remove early emerging broadleaf weeds. “We came back with a tankmix of Loyant at 1 pint per acre plus Clincher at 15 fluid ounces per acre. (Clincher is another Dow product.)”

In another test plot, the researchers tank mixed Loyant with Grasp SC, another Dow AgroSciences product with a different mode of action from Loyant or Clincher.

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