Sudden oak death has caused major damage in California forests and if it makes its way into Kentucky it could have devastating effects on the state’s forests and timber industry.

In an ongoing attempt to keep vigilant on this new threat, plant pathologists and entomologists with the University of Kentucky College of Agriculture conducted surveys in 2004 at nurseries and along parks and public areas. In 2005, they will be working on a field survey of Kentucky forests.

“The reason we are concerned is that Kentucky is on the U.S. Forest Service’s risk map for the disease,” said John Hartman, Extension plant pathologist. “Eastern Kentucky is in the high-risk zone.”

The designation is based on climate and susceptible plants, he said. The fungus thrives in moist, cool conditions along California and Oregon coasts and Kentucky has similar weather in the spring and sometimes in the fall, so it could thrive here. To date, no sudden oak death has been found in Kentucky ..

The disease is caused by a fungus-like organism called Phytophthora ramorum and its origin is unknown at this time.

Forests make up a vast area in Kentucky with more than 11.9 million acres of forestland in the state, according to the Kentucky Division of Forestry. More than $2 billion of revenue is generated annually from the primary and secondary wood industries. The top three species of lumber produced are white oak, yellow poplar and red oak, according to the state agency.

Kentucky has at least half-dozen native plants that are susceptible to the disease but are not killed by it as are oaks. Instead, these plants including rhododendrons, viburnum and mountain laurel, can act as a reservoir for the disease.

Another cause of concern is that despite a quarantine to stop infected plants or the pathogen from moving east, infected plants from a Californianursery were shipped to states primarily in the Southeast in 2003.

In 2004, nurseries and garden centers were examined for plants with symptoms of the disease during a national nursery survey funded by the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service. In Kentucky, 126 nurseries in 28 counties were examined.

UK decided to take the survey a step further in 2004, and collected plant samples from 11 park and natural areas around the state including such places as Bernheim Forest and Mammoth CaveNational Park. Samples were taken from 51 indigenous plants showing some type of disease symptoms. No samples were found to have the fungus.

The next phase of work will begin in March or early April 2005. As foliage begins to emerge, researchers will begin the task of searching for the disease in the state’s forests.

The work is being funding by the U.S. Forest Service and the agency will determine where researchers will make their plant collections.

Hartman noted that this survey aids in a better understanding of the health of Kentucky’s forests. The overall health of Kentucky’s forests is too important to ignore, he said.                                             

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