I saw the weed-chopping crews at work in some cotton and soybean fields during a recent drive across middle Georgia. They were going primarily after herbicide-resistant pigweed, a sight I’ve seen regularly this season, and a good response to a bad problem. But pigweed can and does become hoe resistant, too.
The best made and implemented weed management strategies fall short of perfect. Weeds, particularly Palmer amaranth, will take advantage of any glitch.
In the last few years, Georgia cotton growers have really turned the tide against pigweed and resistant-weed management and should be commended for their efforts. But weather conditions were less than cooperative this spring and early summer (it rarely is cooperative) for optimal weed control.
I recall Stanley Culpepper, University of Georgia weed specialist, saying once that growers have to accept that pigweed is going to kick their tails, and they shouldn’t take the kicking lightly. After the posterior insult, growers can make the right management decision to go after the weed the Old Fashioned way.
The growers getting the crews out there are doing the right thing by removing the weeds but at a great cost. Weeds left to seed will result in more problems the following year and can lead to real crop failure if left unchecked.
But even the tried-and-true technological combination of the hoe and a good swing can fall short of weed-free perfection. Pigweed can resist the hoe, too.
Chopping-resistant weed guide
According to Culpepper, here are some chopping points to remember now and later to keep pigweed from becoming hoe resistant:
- If growers see more than 10 pigweed plants per acre, it’s important to get those plants out of the field.
- An unchopped pigweed will produce 400,000 seeds in dryland cotton production.
- One chopped to 6 inches will regrow and still produce 130,000 seeds.
- One chopped down to 1 inch still produces 36,000 seeds.
- And, finally, if the pigweed is chopped all the way to the soil, well, it can still regrow and have time to produce more than 22,000 seeds before frost comes along.
- Even if you pull it up, it can still resucker if any part of the remaining root touches soil.