 |
 |
 |
|
 |
|
|
|
         |
|
|
|
|
|
|
|
| navigate: home: magazine: fall 2000: article | |
|
College of Agricultural Sciences mobilizes to fight plum pox virus By John Wall | ||||||
|
Reprinted from Penn State Agriculture, Winter/Spring 2000, with updated information, courtesy of the College of Agricultural Sciences. Within four months of the September 1999 discovery of plum pox virus in four orchards in Adams County, the College of Agricultural Sciences and Penn State Cooperative Extension organized and implemented a large educational and testing program that mobilized fruit growers and agricultural agencies to help contain an outbreak of disease that could have crippled Pennsylvania’s fruit industry. Fruit trees in Adams County were found to be infected with the incurable disease, which had never been seen in North America before the identification of the virus. Within two weeks of the initial discovery, four orchards and a fruit tree nursery had been quarantined and restricted from shipping any fruit or nursery stock. Plant pathology and horticultural experts from the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, the Pennsylvania Department of Agriculture’s Bureau of Plant Industry and the College of Agricultural Sciences organized a cooperative program to control and possibly eradicate the virus. A vigorous tree-testing program was started in April 2000. This program will continue throughout the growing season. Plum pox has infected Pennsylvania orchards for at least three years, according to Dr. Herbert Cole, professor of agricultural sciences. Growers noticed signs of disease in 1997 and sent fruit samples for tests when disease symptoms worsened. In 1999, growers took samples to a fruit growers meeting at Rutgers University, where a peach expert who had worked in Europe recognized the signs of plum pox. By October 1999, USDA and the Pennsylvania Department of Agriculture had positively identified plum pox virus as the cause of the problem. The disease, known more familiarly overseas as sharka (Slavic for “pox”), affects stone fruit, including peaches, plums, nectarines and apricots, and some strains of the disease can affect cherry trees. First discovered in Bulgaria in 1915, plum pox virus has slowly spread across Europe, where some 100 million trees have been infected. It also is found in Chile, where it was identified in 1994, and parts of Africa. “Penn State’s primary mission will be to educate fruit growers and other related industries about eradication and/or management of the disease,” Cole said. “Penn State and both the state and federal Departments of Agriculture are focused on solving a very difficult problem.” Penn State has had a comprehensive Web site (http://sharka.cas.psu.edu) up and running since December. Penn State experts also presented a special forum on plum pox in January at the Mid-Atlantic Fruit and Vegetable Conference at the Hershey Convention Center. The College of Agricultural Sciences Information and Communication Technologies unit also produced an eight-page, full-color pamphlet detailing control, management and eradication methods on a six-week deadline. Penn State and the state Department of Agriculture also sponsored a symposium on plum pox, bringing in several European specialists to recommend control strategies. Two videocassettes featuring edited highlights of the symposium are available, as is an educational video on the disease that was released in May. Both the pamphlet and videotapes are available at Penn State Cooperative Extension county offices. “Cooperative Extension agents and specialists have presented about 15 to 20 meetings for different grower groups over the winter and spring,” Dr. James Travis, professor of plant pathology, said. “We are going to work very hard to see that growers have up-to-date information. The pamphlet is designed to be updated every few months, and the Web site will receive regular updates.” In Pennsylvania, the disease will affect primarily peach, nectarine and apricot trees. In 1998, growers in the state produced 65 million pounds of peaches, worth $20.6 million — a crop ranking the state fifth in peach production nationwide. Symptoms of the virus can range from minor to severe. Foliage symptoms at first glance can look like a nutritional deficiency or insect injury. As the disease progresses, lesions can spread to the fruit, making it unsalable. Finally, the disease causes massive reductions in yield, ranging from 80 to 100 percent. “Research on plum pox will be coming in the future, but right now education is our focus,” said Dr. John Halbrendt, associate professor of plant pathology at Penn State’s Fruit Research and Education Center in Biglerville. “The Biglerville facility is equipped to test samples taken from fruit trees in Pennsylvania for plum pox virus. We will be testing samples from weeds in the quarantined area, as well as other plant material.” Tim Gottwald, a USDA statistician, estimates that at least 50,000 samples from trees in Adams and surrounding counties must be tested over the growing season to determine if the virus has spread beyond the initial infected trees. So far, researchers have found further infected acreage in the original orchards, but none beyond the quarantined area. | |||||
| ||||||
© 2002 Outreach Communications, Outreach & Cooperative Extension, The Pennsylvania State University phone: (814) 865-8108, fax: (814) 863-2765, e-mail: outreachnews@outreach.psu.edu |
||||||
