St. Paul, MN (June 1, 2000) ñ Do you realize that plants get sick? When you hear about devastating crop losses, do you think of that loss as a sickness? Whatís being prescribed to keep plants healthy? One important method, thatís been utilized for the last 45 years, uses antibiotics to prevent some of the most serious bacterial plant diseases.
"Bacterial diseases on plants cause significant economic loss each year," says Patricia McManus, assistant professor in the Department of Plant Pathology at the University of Wisconsin-Madison and member of the American Phytopathological Society. "In 1998, for instance, apple and pear growers in Washington and northern Oregon suffered an estimated $68 million in losses due to outbreaks of fire blight, a devastating bacterial disease that destroys apple and pear trees making them appear as if they were torched by fire."
Bacterial diseases such as fire blight are difficult to manage. In addition to visible disease symptoms, bacteria can go into a plantís tissue making it impossible to prune out the disease or effectively apply a pesticide to the plantís surface. Bacteria undergo exponential growth, potentially doubling their populations several times daily depending on the type of bacteria and the environmental conditions. "By the time symptoms are recognized, the bacteria are often entrenched and well on their way to destroying the crop," says McManus. "Thatís why early application of antibiotics to apple and pear blossoms, at least 30-50 days prior to harvest, can be so effective."
Both conventional and certified organic growers find antibiotics to be an essential tool to prevent crop losses from bacterial diseases like fire blight. Here are some basic facts about antibiotic use in the U.S.:
… Only two antibiotics are currently used on plants; streptomycin and oxytetracycline.
… Use on plants accounts for about 0.1% of total antibiotic use.
… Antibiotic use on plants is regulated by the Environmental Protection Agency.
… Controlling fire blight of apple, pear and related ornamental plants accounts for the majority of antibiotic use on plants.
For more information on antibiotics for plant disease control, visit APSís June web feature story at www.scisoc.org. The American Phytopathological Society (APS) is a non-profit, professional scientific organization dedicated to the study and control of plant disease with 5,000 members worldwide. For more information on APS, contact APS Headquarters at 651-454-7250 or http://aps@scisoc.org.