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Presented in partnership with Nufarm Turf & Specialty
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Worst weed in the world
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Yellow nutsedge, an invasive weed, is found on every continent except Antarctica, but it ranks only 16th among the world’s worst weeds. Photo by Billy Warrick |
Although superintendents — and a lot of other people — may be sick and tired of hearing about global warming, it’s here to stay, and it will affect the day-to-day working life of anyone involved in turf and landscape maintenance.
With global warming comes an increase in atmospheric carbon dioxide. As a result, plants in general grow faster and crop yields are higher, but weeds are outstripping crops in their reaction to increased carbon dioxide. For superintendents, this means that grass will grow faster, clipping yields should be greater, and weeds will flourish.
Lewis Ziska, Ph.D., a scientist with the U.S. Department of Agriculture’s Agricultural Research Service, has published several studies on the effects of increasing carbon dioxide on weeds. He has found that warmer temperatures and higher carbon dioxide levels caused weeds to grow to four times their usual height. In addition, when carbon dioxide levels doubled, common ragweed produced twice as much pollen.
In a six-year study published in 2006, Ziska and his colleagues found that increased atmospheric carbon dioxide caused poison ivy to grow faster and larger and to develop a more allergenic form of urushiol, a compound that is a skin irritant to humans. Although carbon dioxide greatly enhanced poison ivy growth, the surrounding trees did not undergo a similar transformation. An increase of woody vines (poison ivy) in the forest ecosystem could contribute to an increase in tree mortality.
Other research by scientists from the USDA-ARS National Soil Dynamic Lab in Auburn, Ala. (Hugo Rogers, Brett Runion, Stephen Prior, Andrew Price and Allen Torbert), and Auburn University (Dean Gjerstad) has explored the effect of higher carbon dioxide levels on two invasive weeds: yellow nutsedge, which occurs in 48 of the 50 states in the U.S., and purple nutsedge, found in the southern and eastern U.S. and in New Mexico, California and Oregon. Both species occur throughout the world, but purple nutsedge is considered “the world’s worst weed,” while yellow nutsedge is ranked 16th.
When grown under high carbon dioxide, both purple and yellow nutsedge had higher instantaneous water-use efficiency and increased plant total dry weight (25.2% increase for purple nutsedge and 10.7% for yellow nutsedge). Purple nutsedge also had greater root biomass, which indicates that a plant is highly competitive. As a result of the study, the researchers believe that both plants, but particularly purple nutsedge, will become more invasive and more aggressive as atmospheric carbon dioxide levels increase.
In a press release from the Weed Science Society of America, Ziska says, “We can no longer assume that the weed control strategies we used in the past will continue to work. ... While researchers explore new approaches, we will need to mix and match the strategies currently available.”
The weeds will be getting bigger and badder, and purple nutsedge may hang on to its title of “the world’s worst weed.”
Bayer Environmental Science announces its Chipco Triton 70 WDG fungicide is now registered for disease control in golf and lawn turf. The water dispersible granule formulation provides broad-spectrum, systemic control of diseases such as anthracnose, brown patch, dollar patch, summer patch, take-all patch, large brown patch, red leaf spot, rust, gray snow mold, pink snow mold and red thread, the company says. Containing the active ingredient triticonazole, the fungicide is said to disrupt membrane function and disease growth. It also is registered for suppression of algae. A new blog to provide an online forum on turf industry issues, trends and regional happenings has been launched by BASF Turf & Ornamentals. BASF Turf Talk, available at www.basfturftalk.com, includes national sales specialists’ field reports, outlooks for the year and tips on reading product labels. Other regular content will cover industry news, events, people and solutions, the company says. |
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