Infected plants from Walmart, Rural King threaten oak trees

A potentially lethal plant pathogen that has killed millions of trees on the west coast has been found in Ohio.

The outbreak is caused by infected rhododendron plants shipped to Walmart and Rural King stores throughout the state, according to officials with the Ohio Department of Agriculture. Approximately 1,600 plants from the infected nursery were distributed. Both retailers have agreed to initiate a recall of the plants.

Although the disease can kill a variety of oak tree species, its origin and impact on the oak tree species is not widely known.

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“Sudden Oak Death is caused by a harmful pathogen that can cause mortality in several oak tree species and also causes twig and foliar diseases in numerous native and non-native ornamental plants, shrubs, and trees within the United States,” Grace Dietsch, a biologist with Five Rivers MetroParks, said. “In California, it is estimated to have killed more than 1 million trees during the last decade.”

Brett Gates, deputy communication director with the Ohio Department of Agriculture , says that the department is taking steps to avoid a widespread outbreak.

“The disease is a federally quarantined species that we are very concerned about spreading to Ohio,” Gates said. “We are taking every precaution to protect Ohio’s valuable oak resource. It is also important to note that Sudden Oak Death has never been found in any Ohio forests, native areas or established landscapes. But it’s important we take every precaution.”

The disease spreads through infected plants and wind-blown rain, as well as contaminated soil and irrigation water. According to the USDA, the fungus thrives in cool, wet climates, but significant infestations can occur in drier conditions in nurseries. Common symptoms of the disease can range from calluses on tree trunks, leaf spots, and twig dieback. However, symptoms are difficult to differentiate from those caused by other pathogens so laboratory analysis is necessary to confirm its presence.

Five Rivers Metroparks confirmed that they haven’t seen evidence of the pathogen in their locations.

“We haven’t found any instances of Sudden Oak Death in Five Rivers MetroParks locations, but have asked staff to be on the lookout for this disease,” said Kristen Wicker, marketing manager for Five Rivers MetroParks.

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Residents who have recently purchased a rhododendron from Walmart or Rural King should monitor the plant for symptoms of disease. The Department of Agriculture also has advised Ohioans who purchased these plants between March and May of this year to dispose of them to prevent spread of disease. Plants can be destroyed by burning, deep burial or double bagging the plant for disposal into a sanitary landfill.

Those who believe they may have an infected plant are encouraged to report on the ODA’s website, or by emailing

“We encourage residents with any questions or concerns to use our online reporting system and we will be happy to follow up with them,” Gates said.

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