Taking the Heat
Talk about a long, hot summer. The summer of 2006 will go down in the record books as one that was particularly harsh. According to the National Oceanic and Atmospheric Administration (NOAA), summer 2006 was the second warmest June-to-August period in the continental United States since records began in 1895. In addition, the 2006 January-to-August period was the warmest on record for the continental United States. Add to that the moderate-to-extreme drought that affected 40 percent of the country, and you don't have to be a turf scientist to realize that the conditions were ripe for turf disease. If you thought turf was especially hard to manage this summer, here's why: “It's literally too damn hot to grow grass,” says Frank Wong, the turf pathology extension specialist for the University of California, Riverside. Wong was part of a panel of turf specialists invited to update golf course superintendents on turf conditions at the California Transition Management Seminar hosted by Bayer Environmental Science the last week in August.
“2006 has been a bad year for disease, and it boils down to temperature,” Wong told the 50 superintendents who attended the event. Because California began experiencing temperatures in May that usually don't show up until late June or July, it forced turf managers all over the state to go into emergency rescue mode. Wong's office had received 250 turf samples since May from turf managers wanting help identifying what's killing off their turf stands. He reported that, despite the heat, anthracnose (usually the No. 1 turf disease problem during California summers) has been declining. “It seems as though turf managers have a handle on it,” Wong said. “A combination of chemical and cultural controls have been effective.”
What was more concerning to turf managers was that what they believed might be yellow patch on their annual bluegrass did not go away in May when temperatures began to increase, and was not responding to fungicides. “Unlike yellow patch, this disease does not go away when it warms up. In fact, it gets worse,” Wong said. “It's very aggressive in growth and goes down to the roots and thatch system.” Wong started seeing samples of this “strange” disease in 2005, and he and his office have been working to identify it. While it does not have an official name yet, Wong and his staff identified isolates of rhizoctonia in the samples. “The big mystery is that we haven't had this pathogen (in turf) in the United States,” Wong said. It has, however, been identified and named in Japan. “We'll probably end up calling it brown ring patch, like they do in Japan,” he said. And it's not just isolated to the U.S. West Coast. “It's suspected to also have been reported in New York, Massachusetts, Connecticut, Illinois, Indiana, Pennsylvania and Maryland,” he said. The good news: Now that it's been identified, researchers are conducting trials to see how effective fungicides are in knocking it out. So far, Wong said, the rhizoctonia disease appears to be sensitive to iprodione, propiconazole and flutolanil.