Ontario growers failing to prevent herbicide drift

RIDGETOWN, Ont. — Herbicide drift can be managed, but the risk may be too great even when the best protocols are in place.

“If there are sensitive crops around you, you can make the decision not to apply a chemical,” said Adam Pfeffer, a development representative with Monsanto.

“If a plant is sensitive to a Group 4 herbicide like dicamba, it tends to be very sensitive.”

Dicamba is a Group 4 herbicide first approved in North American in 1967. It’s a component of Monsanto’s Roundup Xtend product for soybeans, which also includes glyphosate.

Pfeffer said the new formulation should be delivered using “ultra-coarse” droplets through air-induction nozzles in order to limit drift. The challenge is to match the tip to ground speed and pressure.

“We’re not just going to be spraying glyphosate on soybeans any more,” Pfeffer said. “We need two modes of action and we have to keep the drift from reaching other crops.”

Pfeffer said herbicide premixes with three modes of action are already on the market and four modes of action are a distinct possibility in the future.

Ontario Agriculture specialist Jason Deveau said farmers can also slow their ground speed, keep the boom as low as possible and use a greater volume of water.

Proper clean-out protocols with spray tanks should also be followed, he said.

The type of flagging system that was developed at the University of Arkansas to identify crops according to the type of technology being used is another simple but effective measure to avoid human error.

Darren Robinson of the University of Guelph said herbicide drift may be more of a problem in southwestern Ontario than in Western Canada because herbicide sensitive, high-value crops are more common.

Good examples are greenhouse vegetables, wine grapes and sugar beets, the latter being highly sensitive to a wide range of herbicides.

Janice LeBouef, another specialist with the provincial agriculture ministry, said damage to wine grapes from one herbicide drift incidence could have repercussions for many years.

It can take $30,000 to establish an acre of vines, and the production from that acre can easily be worth $10,000 a year.

LeBouef said she had no firm figures to draw on, but she felt spray drift continues to be a significant concern in Ontario despite ongoing efforts to educate growers and develop formulations that reduce its occurrence.

“I’m not seeing it happening less,” she said. “We don’t seem to be getting any better at preventing it. Drift happens a lot easier than many people think.”

She said human exposure to drift is another issue, especially if it moves onto crops such as cucumbers or strawberries that require human crews for the harvest.

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