Eelgrass (Zoster marina)
Image courtesy of Ronald C. Phillips
New R&D Agreement Aims at Natural
Controls for Plant Fungi
By Sarah Tarshis
August 16, 1999
Zosteric acid, a natural product made
by a common seagrass, may lead to a nontoxic way to protect strawberries and
other crops from fungal diseases. Scientists at the Agricultural Research
Service--USDAs chief scientific
arm--are exploring the acid as an environmentally safe alternative to chemical
Zosteric acid is found in eelgrass (Zostera marina L.) that grows in
many saltwater bays and harbors. Under a new Cooperative Research and
Development Agreement, ARS and PhycoGen,
Inc., Portland, Me., will evaluate zosteric acid against fungi that cause fruit
and crown rot of strawberries.
Fungal pathogens rely on spores to infect a plant or fruit, but spores must
first attach to a leaf or fruit surface and then germinate to cause infection.
Unlike chemical fungicides, zosteric acid doesnt kill fungi; rather, it
may act as a shield, preventing spores from attaching. This mode of action
would be environmentally safe and would sidestep the risk of fungi developing
David Wedge of ARS
Utilization Research Lab in Oxford, Miss., will conduct laboratory studies
with strawberries and blueberries, and Barbara Smith with ARS in Poplarville,
Miss., will also conduct greenhouse studies.
Kenneth Curry of the
University of Southern Mississippi will work
with the ARS team to examine zosteric acid's antifungal features. Randall
Alberte of PhycoGen will conduct lab studies on strawberries.
Most research to develop fungicides is done by industry and focuses on major
crops. But the ARS research will benefit small farmers who often grow so-called
minor crops. While grown on relatively few acres, minor crops are
worth about $31 billion annually to U.S. growers and are economically vital to
many rural communities and family farms.
PhycoGen, which manufactures zosteric acid, will also cooperate with ARS to
develop a product to protect stored seeds from fungi. The company is also
exploring the acid as a marine antifouling agent for boat hulls and other
Scientific contact: David Wedge, ARS
Natural Products Utilization Research Unit, National Center for Natural Product
Research, University, MS, phone (601) 232-1137, fax (601) 232-1035,