Glyphosate-Resistant Canada Fleabane on The Move!

Glyphosate resistant Canada fleabane (conyza canadensis) has infested over 200,000 acres of cotton in west Tennessee in 2002, representing 36% of all cotton acreage in the state. A number of factors played a role in the severity of this outbreak, such as weather, the mass seed production and dispersal of canada fleabane, and the increased use of glyphosate tolerant cotton.

It has been two years since populations of glyphosate resistant Canada fleabane were found in three fields in the State of Delaware. Growth room trials conducted by Mark VanGessel at the University of Delaware showed that up to 10 times the normal field rate of glyphosate was needed to achieve the same level of control as a susceptible population. Shortly after, resistant populations appeared up in New Jersey and Maryland.

In Ontario and across the U.S., acreage of glyphosate tolerant soybeans has risen dramatically. Glyphosate tolerant corn has been gaining popularity. Learn from the mistakes of others! Avoid overuse of glyphosate! Use glyphosate products in situations where they will provide the greatest benefit to your production system. Increased selection pressure (continual use) of any herbicide will ultimately lead to either weed shifts or resistance. Minimize the risk of developing resistance by following a diverse crop and herbicide rotation.

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