Glyphosate Resistant Pigweed: Start With Plan, Add Hoes and Hoods

January 3, 2012

This week, I attended the annual Cotton Consultants meeting at the Beltwide Cotton Conference in Orlando. And, by the way, was too cold in sunny Florida to even consider sneaking off to Disney World or other Orlando escapes. With a high of 45 degrees outside, I wasn’t even tempted to visit Mickey Mouse.

No one who sat through “Myths and Facts of Pigweed Control” could have left the room with any doubt that glyphosate weed resistance is serious business. Below are some comments made by speakers:

Bob Nichols, Cotton Incorporated:

“If you are in a county or next to a county or even two counties away from a county with pigweed resistance then you should treat with a systems approach beginning with pre-emerge compounds.”

Larry Steckel, University of Tennessee:

Glyphosate resistance has changed everything and “nothing is going to be as easy as it once was.” Steckel provided a list of 9 glyphosate-resistant weeds in the southern US with “Palmer pigweed as the driver going forward.” 300 southern counties show resistance and no new herbicides are on the horizon.

Steckel asked if anyone really wanted to go back to using hooded sprayers, and then said the answer didn’t matter. He told consultants this was not a choice. To gain any control over resistant pigweed they had to use a pre-emerge with a return to hooded sprayers for good coverage and a scheduled spraying plan. “Otherwise, the future of weed control is chopping crews.”

Ken Smith, University of Arkansas:

Smith, talked about the need for the culture of weed control to change by going into the season with a plan, better yet a written plan. He told consultants that they needed to help growers by building a prescription for weed control.

Smith’s suggestion is to start overlapping residual herbicides to catch escapes – 7, 14, 21 day increments.”

Proper hand hoeing is more than chopping pigweed so it’s not visible above the cotton canopy. A pigweed plant has viable seed at 3/4 inches tall so the plant should be taken out as completely as possible. Zero tolerance is the only way to manage pigweed seed.

To demonstrate how many pigweed seeds could come from one plant, a count from 1 very large Palmer Pigweed turned up 1.8 million seed.

Jason Bond, Mississippi State University:

Bond addressed the often overlooked area of weed control on turn rows, ditch banks and other non-cropped areas of the field. Pigweed grows equally well in these areas and drops plenty of the small seed during the growth cycle. He suggests careful use of herbicides based on the labels and getting adjoining neighbors to cooperate in weed control.

Andy Vanglider, Arkansas Extension Agent, Clay County:

Vanglider talked about success in his county using the idea of Zero Tolerance and guidelines established with Ken Smith. His emphasis in 2011 was to make the farm community aware of the immediate need to address glyphosate resistance. He anticipates adjoining counties will become part of the effort for 2012.

2 Responses to Glyphosate Resistant Pigweed: Start With Plan, Add Hoes and Hoods

  1. Tim Dunnam on March 19, 2012 at 7:06 pm

    In dealing with this weed resistence problem there is no single answer.One of our aerial applicators/producers in eastern Arkansas had good success on pigweed and other weeds last year using a specialized surfactant that lowers the ph of the spray solution to match the ph of the herbicide thus preventing chemical hydrolysis, or deluted herbicide. This along with hooded sprayers might be another option.

  2. Debra L Ferguson on March 27, 2012 at 9:32 am

    Hi Tim: Thanks very much for the insight. Could you shared exactly what the name of the specialized surfactant used by the applicator?

Leave a Reply

Your email address will not be published. Required fields are marked *

Facebook – Here We Are!