There may be only two types of farmers in Indiana – those who already have Palmer amaranth and know how tough it is, and those who will cross paths with the knock-out weed in the near future. If that's true, Mark Lawson, a Syngenta agronomist and farmer near Danville, Ind., says you ought to assume you have it and plan a herbicide program for next year that will nail it if it's there and not let it get started.
The catch is it's a return to $50 to $60 per acre weed control per acre. That may be something you think twice about before doing.
"The alternative is to take your chances," Lawson says. "Scout for it and if you see one or more, even in a fence row or road ditch, dig it and burn it. The problem with this weed is that it grows big and grows fast, chokes out other weeds, and produces up to a million seeds per plant. If you just ignore it should it show up as a few plants one year, within two or three years you'll have a whole field infested. Then you either pony up on herbicide cost, or hire migrant labor at three times the cost to hand pull it, get it out of the field, and burn it."
They've done that in the South. It's also caused farmers in the South to change crop rotations so that they can better control it. What Lawson and Bill Johnson, Purdue University weed control specialist, both hope to sound the alarm until farmers respond and take notice. One step is identifying the weed and getting rid of it when you first find it. The second is designing a herbicide program that will knock it out if it's there.
Just how bad can it be? Remember the commercials where they hold up a lit match and say this is a flame, then show you a blowtorch or inferno to show how much better their product is. Johnsongrass is a match. Giant ragweed is a match. Palmer amaranth is the blast furnace!