St. Paul, Minn. (October 15, 2001)—Right now in some of California’s most scenic areas, thousands of beautiful, stately oak trees are dying from a new disease never seen before in the United States and scientists have few clues about how to stop it. In Florida, more than $200 million has been spent trying to control Citrus canker, another plant disease new to this country. Yet despite intense efforts the disease keeps spreading.
Problems like these may become more common, say plant health scientists, as new diseases make their way into the U.S. In an effort to assist regulators, the world’s largest organization of plant health scientists, The American Phytopathological Society, is preparing a “most wanted” list of diseases posing the greatest threat to U.S. agriculture and forestry.
"We have always been vulnerable to diseases from other countries,” states Dr. Larry Madden, a plant pathologist at Ohio State University. “But with increasing world trade and more people traveling, the threat has increased substantially in recent years.”
Imposing trade regulations to hinder the diseases’ spread seems most appropriate, and some have helped. But in order to enact them, the World Trade Organization, whose task is to facilitate international trade by standardizing approaches to certain trade policies, requires valid scientific evidence for any requested restriction. While APHIS routinely conducts risk assessments for various diseases, there are so many potentially threatening ones that a detailed analysis of each of them is virtually impossible, say scientists.
“Simply because a pathogen is identified as a threat does not mean it will ever appear, or if it does, that it will do so in a way that causes substantial destruction,” states Madden. “The reverse is true as well,” he adds, “with diseases of seemingly small impact sometimes surfacing to cause great damage.” This puts enormous pressure on regulatory agencies, primarily the USDA Animal and Plant Health Inspection Service (APHIS), to develop sound and defendable regulations.
To help agencies like APHIS, plant health scientists with the American Phytopathological Society (APS) began work last year on a “most unwanted” list of diseases. Led by Madden, an APS member, and composed of scientists and government regulators, the group identified 42 possible diseases of concern. “The tough part now,” says Madden, “will be determining which diseases pose the greatest threat.” Previous attempts to predict such things have been difficult.
According to Madden, a more accurate assessment of a disease’s possible threat often arises when a greater number of people can be involved in the discussion. With that in mind, APS has recently posted its list online and is inviting comments from its members and others with a special interest in this area.
“This is a challenging task; but not an impossible one,” notes Madden. “Our goal is to end up with a ‘live’ online list that can be continually monitored and updated as new information is received. We’ve made substantial progress, but we still have a lot of work to do.”
Identifying exotic pathogens of potential threat to the U.S. is the subject of the recent APSnetfeature and can be found at www.apsnet.org/publications/apsnetfeatures/Pages/Nonindigenous.aspx. The American Phytopathological Society (APS) is a nonprofit, professional scientific organization dedicated to the study and control of plant diseases, with 5,000 members worldwide.