Md. on alert for disease in oaks

August 31, 2004

ANNAPOLIS - The Maryland Department of Agriculture, in cooperation with the University of Maryland Cooperative Extension, is offering free testing to home gardeners who question whether plants they have purchased are affected by sudden oak death disease.

SOD is a fungus-like disease that attacks many types of plants. It causes symptoms including leaf spots, cankers, dieback and death on certain types of nursery plants. Some plants can be carriers, spreading SOD into natural areas where it can infect and kill trees, including oaks. The disease, which poses no threat to humans, can spread many ways, including by air and water.

Maryland has two confirmed SOD-positive samples from rhododendron and camellia plants. To date, SOD has only been found in nurseries and has not been found on oaks in Maryland.

"With the extensive rainfall we've had this year, if the disease is present, plants will likely be showing symptoms now," said Agriculture Secretary Lewis R. Riley. "We don't know how widespread this disease might be and we don't want to take any chances.


"That is why is it critical that residents contact the Home and Garden Information Center if they think they have plants exhibiting symptoms for Sudden Oak Death. Depending on the climatic conditions, this disease could seriously affect our nursery industry and forests."

The testing will target symptomatic host plants purchased between March 2003 and March 2004 from Maryland nurseries and garden centers that received plants from Monrovia Growers in Azusa, Calif.

The testing also will target azaleas and rhododendrons purchased from Lowe's Home Improvement stores between February 2003 and May 2004 that were supplied by an Oregon nursery testing positive for SOD.

The only way to confirm the disease is through laboratory testing. Home gardeners may submit samples from symptomatic host plants including rhododendron, azalea, lilac, camellia, viburnum and pieris to the Maryland Home and Garden Information Center.

This disease affects only the foliage or small branch tips, so only leaves with suspicious spots or small twigs should be submitted for testing. Do not submit healthy-appearing leaves, as these cannot be tested for the disease.

"There is no need to be alarmed if the plant is healthy, but we encourage people to closely monitor plants to see if symptoms do develop," said Carol Holko, acting chief, MDA's Plant Protection and Weed Management.

To report possibly infected plants or for information, contact the Maryland Home and Garden Information Center at 1-800-342-2507 or on the Web go to Out of state, call 410-531-1757. Information is available by logging onto (click on P.ramorum, "Sudden Oak Death" Information).

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