Cases of a plant disease known as sudden oak death has been confirmed in Missouri by the Missouri Department of Agriculture and the USDA Animal and Plant Health Inspection Service.
Sudden oak death has been detected on rhododendron plants that were shipped to some retail nurseries in Missouri, including Walmart and Rural King stores throughout the state.
Shipments were sent to Walmart stores, Springfield Home Depot, Stark Bros. Nursery Garden Center in Louisiana, Missouri, and Fort Leonard Wood PX, as well as Rural King stores. A representative at the Walmart Garden Center at 401 Supercenter Drive in Jefferson City said they did not receive shipments of the affected plants.
Rhododendrons or lilac plants of the known infected varieties labeled Park Hill Plants that were purchased between March and June should be disposed of immediately.
Specific varieties of rhododendrons that have tested positive for the disease are Cat Cunningham Blush, Firestorm, Holden, Nova Zembla, Percy Wiseman, Roseum Elegans and Wojnars Purple. Lilac varieties that tested positive are Common Purple and Persian Lime.
The Department of Agriculture warns consumers to destroy any of these plants by burning, deep burial or double-bagging the plant, with the roots, in heavy duty trash bags to be disposed at a sanitary landfill.
Consumers who don’t know what variety of plant they have should look for symptoms of the disease, including wilting or browning leaves, leaf sports and twig dieback.
According to the Department of Agriculture, sudden oak death is a form of ramorum blight which is caused by a fungus-like pathogen. The plant disease has effected some types of oak trees in California and Oregon since the 1990s, but hasn’t established itself in the Midwest.
The shipment of the rhododendrons has been traced back to Park Hills Plants in Oklahoma, and may have originated from nurseries in Washington and Canada. According to the investigation, shipments were sent to at least 18 states.
Sudden oak death, according to the USDA-APHIS, is dangerous because of its ability to affect a wide variety of trees, shrubs and plants, and because there is no known cure. However, no evidence that this disease can be passed to humans or animals has been found.