What is in this article?:
- Managing the mounting pain of pigweed
- Pre-emerge herbicide necessary
- Arkansas weed scientist Ken Smith is recommending that growers include as many weed control options as they have at their disposal – cultural, mechanical and chemical – to keep the pain of glyphosate-resistant pigweed manageable.
- Smith spoke to farmers attending the PigPosium, in Forrest City, Ark., sponsored by the Arkansas Cooperative Extension Service and Farm Press.
- The symposium, attended by close to 800 people, focused on the impact of glyphosate-resistant pigweed.
Pre-emerge herbicide necessary
If you’re going to control pigweed in the Roundup Ready system, a pre-emerge herbicide is essential. Start clean. Apply Reflex prior to planting or Cotoran, Direx or Caparol pre-emergence.
While pre-emerge herbicides are effective, little if anything will provide 100 percent control. For that reason, proper hand hoeing has to remain an option, according to Smith.
“If you’re running a hoe crew, walk behind them just to make sure they’re doing it correctly. Adventitious buds at the base of the plant will come back.”
For post-emergence applications on Roundup Ready cotton, Smith recommends applying Roundup plus Dual at 2-leaf cotton. “Don’t wait for the 3-leaf stage. If pigweeds germinate, we’re behind, so don’t let them germinate. Then, apply Roundup plus Dual at 6-8 leaf, scout and be prepared to post-direct. Apply Valor plus MSMA at layby.
LibertyLink cotton and Ignite herbicide is also an option for producers, according to Smith. But residuals must be used with this technology as well.
Smith noted that some cotton producers “are going to plant WideStrike cotton and treat with Ignite. I think you should treat it like it was Roundup Ready Flex and scout closely for weeds. But if the weeds germinate, you have to spray with Ignite. If you do this, be prepared to lose two nodes of cotton. The yield number that farmers keep telling me is 200 pounds. It doesn’t happen every time, but be prepared.”