Farm Progress

When to apply glyphosate to Roundup Ready alfalfa

Glyphosate may be applied to herbicide-tolerant alfalfa at any state from preplant to five days before cutting.An early application of glyphosate is encouraged.

Karen McMahon 2

June 13, 2011

1 Min Read

The first fields of Roundup Ready alfalfa are being planted and managed this year since USDA deregulated the crop. Crop protection companies are suggesting how growers of the herbicide-tolerant alfalfa can manage the new crop’s weed control program.

Syngenta states that glyphosate can be applied to the herbicide-tolerant alfalfa at any stage of growth from preplant to five days before cutting.

Syngenta cites a study conducted by the Panhandle Research and Extension Center, Scottsbluff, NE. The study found that if weeds were removed using glyphosate shortly after alfalfa emergence and again in several weeks after later flushes of weeds had emerged, the alfalfa plant could be protected from weed interference and stand establishment could be further enhanced.

“This study found that removal of weeds at the unifoliate and again at the fourth trifoliate growth stages provided the greatest alfalfa yield,” reports Cole Anderson, Syngenta field agronomist. “Of course, the more weeds removed, the higher the quality and yield potential in your establishment year.”

A small percentage of seeds in the bag may not have the herbicide tolerance traitalfalfa.jpg; therefore an early application of glyphosate-based herbicide is encouraged to remove these plants before they become dominant plants within the stand.

Growers are encouraged to talk to a local agronomist or seed dealer to understand how to implement an integrated weed management practice in the alfalfa stand. The amount of glyphosate used should be dictated by the type and density of weeds. 

About the Author(s)

Karen McMahon 2


Karen McMahon has been editor of Farm Industry News since 2000. She joined the staff in 1998 as senior editor and previously worked on the company’s National Hog Farmer magazine.

Karen grew up on a crop and livestock farm outside of LeMars, IA, and earned her journalism degree from South Dakota State University. After college, she worked on the local newspaper as farm editor and later started writing for various livestock and crop magazines.

She has written extensively about trends and technology related to corn and soybean production, the equipment needed for row-crop farming, and livestock production.   

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