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Presented in partnership with Nufarm Turf & Specialty
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Herbicidal turf
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Fine fescue turf that does not exude a weed-suppressing chemical is shown (left) next to a plot of Intrigue chewings fescue, which produces m-tyrosine, a compound that suppresses weeds. Photo by L. Weston |
A grass with its own herbicide? A grass that actually prevents weeds and other plants from encroaching? It sounds too good to be true.
For thousands of years, scientists have known about allelopathy, the suppression or destruction of one plant species by another through chemical means. However, many scientists believed that allelopathic effects were weak, that the chemicals produced by plants were not strong enough to significantly affect neighboring plant species. Recent studies using more sophisticated methods have found that some plants, particularly some grasses, can exude highly toxic chemicals through their roots, and these chemicals can cause significant harm to nearby plants that are not of the same species.
Some fine fescues are known to be allelopathic, and recently scientists at Cornell University evaluated 80 fine fescue cultivars in the field and the lab and found that eight of them had “strong weed suppressive potential.” Based on these studies, the scientists selected Intrigue, a turf-type chewings fescue (Festuca rubra L. subspecies commutata) cultivar (Turf Merchants Inc.), for further study.
The group at Cornell was able to isolate the allelopathic compound in the root exudate of Intrigue chewings fescue and identify it as m-tyrosine. They also analyzed other fine fescue cultivars and related species and found large amounts of m-tyrosine in root exudates of all cultivars of Arizona fescue (F. arizonica), creeping red fescue (F. rubra subspecies rubra) and chewings fescue. In contrast, hard fescue (F. longifolia), sheep fescue (F. ovina) and Idaho fescue (F. idahoensis) did not produce detectable amounts of m-tyrosine. In fact, m-tyrosine has only been detected in one other plant, myrtle spurge (Euphorbia myrsinitis), which is considered a noxious weed in the U.S, and there are no known reports of m-tyrosine in soil.
Root growth of fescue plants that produce m-tyrosine was not affected by applications of the compound, but root growth of plants that do not produce m-tyrosine was strongly affected.
The scientists at Cornell concluded that several fine fescue species produce large amounts of m-tyrosine, which inhibits growth in a wide range of plants, particularly large crabgrass, dandelion, mustard and other small-seeded weeds. The compound is unique because it is highly toxic at very low concentrations and it is released through the plant roots.
Ongoing research is aimed at discovering more about the mode or modes of action of m-tyrosine and determining whether it has the potential to be used as the active ingredient in herbicides that would offer less risk to humans, wildlife and the environment.
Editor’s note: The research described here was the basis of M.S. and Ph.D. research performed at Cornell University by Cecile Bertin, in the laboratory of Leslie Weston, Ph.D. The chemical identification work with m-tyrosine was performed in the lab of Jerrold Meinwald, Ph.D., at Cornell under the direction of Frank Schroeder.
The Crop Science Society of America’s Turfgrass Science Division annually gives awards to graduate students in the field for oral and poster presentations at its annual meeting. In the Turfgrass Management, Oral category, John Inguagiato, Rutgers University, and Thomas Serensits, Penn State University, tied for first place, while Lindsey Hoffman of University of Massachusetts took second, and Joshua Summerford of University of Arkansas took third place. In the Soils and Greens Mix, Oral category, John Stier of Wisconsin, Madison, won first place; Jared Nemitz of Purdue University won second place; and Purdue University’s Adam Moeller won third place. Ewing Irrigation Products has enhanced its Turf & Erosion Control Products division with the appointment of Mike Blume as national sales manager. This is the latest step in the company’s plan to implement a national sales and product management strategy for turf and erosion control products, it says. In addition to the company’s agronomic development of its Turf & Erosion Control Products division, Blume also will manage the company’s Turf Products sales team. |
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