April 14, 2004 | By: Laura Skillman
PRINCETON, Ky.

Herbicide resistant weeds are a growing concern to agriculture and one such weed that is causing concern in many surrounding states is annual ryegrass.

To determine the difficulty in controlling this weed, scientists with the University of Kentucky College of Agriculture are conducting a survey in wheat fields across the state.

While no resistant ryegrass has yet been discovered in Kentucky , there is cause for concern, said Jim Martin, weeds science specialist with theUniversity of Kentucky Cooperative Extension Service . There has been resistance found in Tennessee , Arkansas , Virginia and North Carolinato the herbicides Hoelon or Accase inhibitors. These are also the only options available for Kentucky growers for control of ryegrass in wheat.

Some ryegrass biotypes are resistant to glyphosate and Accent but fortunately they are not in this region, he said.

Annual ryegrass is one of the more difficult cool season grasses to control and is especially difficult once it overwinters and becomes established, Martin said. The grass can limit tillering in wheat and can also have a negative impact on no-till corn.

In Kentucky , there have been cases of multiple applications of Hoelon that failed to have an adequate control of ryegrass in wheat. Varying levels of control using glyphosate as a burn down control in no-till corn has also been observed.

“While there’s no evidence of glyphosate resistance, we do suspect that there may be varying levels of tolerance that may explain what we’ve seen over the years,” he said.

Martin and Bill Witt, UK weed specialists, are working with funding from the Kentucky Small Grain Growers on a survey to evaluate possible resistance to herbicides used on this weed in Kentucky .

One reason for the survey is to develop a database that can be used should the need arise to request special labeling of experimental herbicides that may be used in the management of ryegrass, Martin said.

Any producer in Kentucky who is having difficulty managing this weed in their wheat fields can participate in this survey without cost to them. Anyone interested in participating or learning more about the survey can contact their local Cooperative Extension office.

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Contact: 

Writer: Laura Skillman 270-365-7541 ext. 278
Source: Jim Martin 270-365-7541 ext. 203