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 From the News Desk...Now is the time to think about spring dead spotby John ReitmanDoug Lowe, CGCS, and the members at Greensboro (N.C.) Country Club, know that spring dead spot is something they will have to contend with pretty much every year. “SDS is something I and my members for the most part know will be there every spring without fail,” Lowe said. “I think like a lot of superintendents, we map out areas every year in the spring without fail.” Even in the first full week of autumn now is the time for Lowe and other superintendents growing Bermudagrass along the East Coast and throughout the Southeast to begin thinking about spring dead spot, or more importantly, how to prevent it. The fungus that causes spring dead spot, Ophiosphaerella korrae, is active throughout the fall and winter months. If present, the pathogen makes a Bermudagrass plant that already is stressed by agronomic, climatic or physical factors more susceptible to the disease, said Lane Tredway, Ph.D, turfgrass pathologist at North Carolina State University. The pathogen attacks and rots roots, rhizomes and stolons. Once the fungus is established, it clogs the plant’s vascular system, disrupting its ability to take up water and nutrients, thus making it susceptible to the effects of winter-related injury. Putting greens typically are more susceptible than turf in areas with a higher height of cut. “There are no reactive control measures. Either you prevent it, or you look at it all summer.”It is important to take pre-emptive steps to try to avoid it, or be resigned to staring at its effects next spring and summer, said Tredway, who recently wrote on the topic on TurfDiseases.com , a blog he maintains with other turfgrass scientists. Research conducted at North Carolina State indicates that spring dead spot can be managed successfully before Bermudagrass goes into dormancy with one or two fungicide applications in the fall as well as aerifying with hollow tines – 3 inches to 4 inches in length - one to three times per year. Although spring dead spot can be costly in that it adversely affects playing conditions, preventing it also is an expensive proposition. “I dedicate about $6,000 for treatment each year, which treats about 10 acres,” Lowe said. “Some years the treatments are better than others and there always seems to be some pop up in new areas. We talk about this every year with the green committee. But as long as we control the worst areas, they seem to generally accept these areas will recover by early summer.” Rubigan has been the most effective fungicide at managing spring dead spot in North Carolina State’s trials. Research also shows that it is critical to make fungicide applications when soil temperatures are 60 degrees and 80 degrees Fahrenheit. Bermudagrass typically begins to go into dormancy when soil temperatures drop below 60 degrees. According to Tredway, two applications of Rubigan 30 days apart at 4 ounces per 1,000 square feet have been effective at helping control spring dead spot in the eastern United States. On greens, he suggests a total of 12 ounces per 1,000 square feet, either in two 6-ounce applications or three 4-ounce treatments. Other products that have been effective in trials at North Carolina State’s Lake Wheeler Turf Field Laboratory in Raleigh, include Banner Maxx (two applications, 4 ounces per 1,000 s.f.), Headway (two applications, 3 ounces per 1,000 s.f.) and Eagle 20EW (two applications, 2.4 ounces per 1,000 s.f.). Because the pathogen attacks plant roots, it is critical to the success of any preventive fungicide program to water in all fungicide applications to get the product where it is needed most, Tredway said. The same palette of fungicides that have been successful at controlling Ophiosphaerella korrae in North Carolina State’s trials have been largely ineffective at managing spring dead spot in the Midwest, where Ophioshpaerella herpotricha is prevalent, Tredway said. This has led some researchers and turf managers to conclude that another pathogen, perhaps Ophioshpaerella herpotricha, is responsible for spring dead spot in that part of the country. “There definitely is,” Tredway said. “The question is whether or not that other species is more difficult to control with fungicides. Our research in North Carolina says no.” In fact, trials at North Carolina State have been successful at controlling Ophioshpaerella herpotricha as well, causing research scientists to conclude that other factors, such as soil conditions are at work in the Midwest. Regardless of geographic location, the key to successfully managing spring dead spot is to treat preventively and early. “There are no reactive control measures,” Tredway said. “Either you prevent it, or you look at it all summer.” |
In other news... Study examines spring pre-stress fertility programs Research finds no correlation between biostimulant applications before spring core cultivation and recovery. Posted: 09/02/2010 Read more » Aquatrols, TurfNet present Water Week The series of five Webinars is aimed at helping superintendents manage water and soils more efficiently. Posted: 09/01/2010 Read more » News and people briefs Registration opens soon for Irrigation Show, Briggs & Stratton elects new chairman, FMC taps new director for professional solutions division Posted: 09/01/2010 Read more » GCSAA selects firm in search for new CEO Kansas City-based company will open search process for Mark Woodward's successor in October. Posted: 08/31/2010 Read more » Water foul! Research shows that droppings from non-migratory geese on turf can result in nitrogen runoff into adjacent bodies of water. Posted: 08/26/2010 Read more » Complete news index » |
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