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Optica Trio: a new herbicide for Group 2 resistant pests

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Published: February 17, 2011

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A new broadleaf herbicide has been approved for control of some of Western Canada’s peskiest of cereal crop pests.

Broadleaf control in cereals was once a simple matter of applying a Group 2 herbicide in the four to six leaf stage and waiting for harvest.

A few weeds developed resistance to Group 2, while others that were a minor problem in tillage systems have become major headaches under zero till.

Ken Sapsford of the University of Saskatchewan’s Crop Development Centre is welcoming a new combination of Group 4 herbicides to look after some of these aggressive yield robbers.

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“While it isn’t a new mode of action, it is still good when we get a new tool that farmers can use,” he said about UAP’s new combination of MCPA, dichlorprop-P and mecoprop-P.

Producers had previously been able to combine the venerable Group 4 chemicals that comprise Optica Trio on their own, but UAP has delivered them in one container and in an amine formula that appears to improve the efficacy.

Brodie Blair of UAP said Agriculture Canada and U of S researchers encouraged his company to develop and register the herbicide.

“They really expressed a desire to have this for prairie farmers,” he said.

“It’s not a co-pack. This is a premeasured blend. And we’ve registered it for tank mixing with clodinafops, Horizon or Ladder. And with Everest (flucarbazone) as well.”

These mixes are designed to control a greater spectrum of broadleaf weeds as well as wild oats and green foxtail. Yellow foxtail control is an added benefit from mixing with clodinafops.

Sapsford said the combination product showed that it can control larger, later stage weeds as well as the usual post-emergent small-stage pests.

“That could be useful with all the wet conditions that are potentially out there this spring.”

He said the new herbicide’s strength remains with the Group 2 resistant kochia and cleavers.

“Eighty-five to 90 percent of kochia in Western Canada and about 40 percent of the cleavers in Alberta are Group 2 resistant. We need some more tools and this looks like one,” Sapsford said.

Blair said Optica Trio doesn’t solve all weeds problems in cereals. It particularly comes up shy when dealing with narrow-leaved hawk’s beard and hemp nettle.

For that, UAP is working on a future registration of a thifensulfuron and tribenuron co-pack product.

Optica Trio facts

What is it?

An amine formulation of MCPA, dichlorprop-P and mecoprop-P

What crops is it for?

Wheat, durum, barley and oats

What does it control?

Stinkweed, wild mustard, lamb’s-quarters, volunteer canola, redroot pigweed, common chickweed, kochia, common ragweed, wild buckwheat and cleavers

What weeds does it suppress?

Lady’s-thumb and Canada thistle

What weeds won’t it suppress well?

Narrow-leaved hawk’s beard and hemp nettle

About the author

Michael Raine

Managing Editor, Saskatoon newsroom

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