Weed Control Tips From Purdue’s Bill Johnson

USDA’s Crop Progress Report on Tuesday showed 92% of Indiana corn and 88% of soybeans have been planted. So, with planting all but complete, we turn our attention now to weed control.
“The big monster in the room right now is the June 12 cutoff date for Dicamba applications in Xtend soybeans,” says Bill Johnson, professor of weed science at Purdue University. He was a guest on the latest Purdue Crop Chat podcast, found now at hoosieragtoday.com.
He says that with this dry weather, weed emergence has been slow.
“What a lot of guys are kind of agonizing over now in terms of weed control in soybeans is number one, do I put a post treatment out there when I don’t see a lot of weeds? Number two, do I need to layer on that group 15 residual herbicide for waterhemp, nightshade, things like that, when I don’t see any that are emerged yet?”
Johnson answers, “With residual herbicides, unless they’re degraded by sunlight or they’re volatile, I would spray them because eventually it will rain. And even if you don’t get a lot of activity on the first flush of weeds that comes up, that herbicide is still laying there and it’s going to help you out later in the growing season.”
In both corn and soybeans, Johnson adds, “Anything planted in the last two weeks or so is very unlikely to have gotten enough rain to activate the pre-emerge herbicides, and so those fields could arguably require treatment earlier than the ones that were planted earlier and got the rain on the pre-emerge herbicides.”
For soybeans, Johnson says the good news is that if you’re in an Xtend system, you still have the ability to use RoundUp and Liberty in those fields after the June 12th dicamba cutoff date.
Hear more with Johnson and Purdue Extension’s Dan Quinn and Shaun Casteel in the Purdue Crop Chat podcast. Download it below or wherever you listen to podcasts.

Recommended Posts

Loading...