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John Reitman

By John Reitman

Alternatives for glyphosate depend on the application

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Jim Brosnan, Ph.D., right, says he is fielding more questions about glyphosate this year than at any other time in his career.

Granted, glyphosate is not the most widely used product on the shelves of golf course maintenance facilities, but recent claims regarding its safety are a wakeup call that it's never too early to start looking for alternative solutions to chemistries with a questionable future.

"You know, I've gotten a lot of glyphosate questions in 2019, probably more this year than from 2008 to 2019 combined," said Jim Brosnan, Ph.D., professor and weed specialist at the  University of Tennessee. "It's not just me. My colleagues in row crops give a talk on soybeans and all the questions are about Roundup.

"We as a weed science group, we need to do something to educate our extension agents who are getting these questions from people in Tennessee."

Superintendents likely use glyphosate for spot treating weeds in non-grassy areas, or to clear wide swaths of turf during renovation projects. But chances are increasingly likely that someone somewhere sometime is going to question you for using it, if they have not taken that option away from you by then.

If and when that time comes, and it probably will, there are many options available to golf course superintendent, depending on the application, said Ohio State professor and weed scientist David Gardner, Ph.D.

"There's three areas where I can see glyphosate being used on a regular basis on a golf course one is on hard surfaces, you know, cracks in the concrete, for example. And in those instances, there's all of the acceptable substitutes in the world that are available, so that's not a problem," Gardner said. "Second place where they would use Roundup with some frequency would be on weed control in ornamental beds. And the particular advantage of using glyphosate, there's very few selective weed-control options and none of them are for broadleaf weed control. So you could make a decent argument that Roundup is really the better choice for them.

You know, I've gotten a lot of glyphosate questions in 2019, probably more this year than from 2008 to 2019 combined. . . . we as a weed science group, we need to do something to educate our extension agents who are getting these questions from people in Tennessee.

"The real issue then would be when they're using glyphosate for renovation and reestablishment purposes. And glyphosate is the only non selective herbicide that's truly systemic. There is some systemicity with glufosinate, but it's relatively limited. In other words, people usually don't use that herbicide in a renovation project for a reason."

Glyphosate has been blamed for causing cancer in more than 13,000 suits, and two juries have awarded more than $180 million in damages in two cases. 

Still, glyphosate possesses other traits that make it a more attractive option than many of the alternative herbicides.

"Its environmental profile is actually very good," Gardner said. "It's not likely to leach.

"Since it binds so tightly to soil particles after application, the advantage of that is that you're permitted to re-enter the area with seed seven days after application. There's a lot of non-selective herbicides out there that are systemic. The problem is that their soil residue is so long that you would have to wait for a very, very long time before you went back into the area. And so, probably from a from a golf course superintendent standpoint, I would think that that would be the most important cause for concern for them."





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