Sudden Oak Death (SOD) in Georgia

Sudden Oak Death (SOD) was first reported in 1995 in central coastal California. Since then, tens of thousands of tanoaks (Lithocarpus densiflorus), coast live oaks (Quercus agrifolia), and California black oaks (Quercus kelloggii) have been killed by the fungus, Phytophthora ramorum. On these hosts, the fungus causes a bleeding canker on the main stem of the tree which grows over a period of several years until it girdles the tree. This effectively eliminates the tree's ability to move adequate amounts of water from the roots to the crown. On the host plants the fungus causes leaf spot and twig dieback, and doesn't kill these species. The hosts serve as spore factories for the fungus which can inundate a forest understory under the ideal environmental conditions.

As of January 2002, the disease was known to occur only in California and southwestern Oregon; however, transporting infected host plants may spread the disease. The pathogen has the potential to infect oaks and other trees and shrubs elsewhere in the United States. Limited tests show that many oaks are susceptible to the fungus, including northern red oak and pin oak, which are highly susceptible.

In March of 2004, select camellia varieties from a nursery in California were identified as being infected with the pathogen. Two other nurseries in Oregon were also found to have infected plants in the summer and fall of 2004. A total of 59,000 potentially infected plants were shipped to Georgia. While 10,000 plants were intercepted by the Department of Georgia Agriculture, 49,000 plants were sold before Georgia was informed of the SOD infected shipment. It is unknown how many of these 49,000 plants, if any are infected. Sudden Oak Death pathogen has now been found in 17 nurseries throughout Georgia.

Georgia Department of Agriculture nursery inspectors inspect plants imported into our state, and continue to intercept some infected nursery stock each year. The Georgia Forestry Commission samples native vegetation surrounding these nursery sites as well as from forested areas throughout the state and to date, no native plants have been infected with this pathogen in Georgia. The Georgia Forestry Commission continues to work closely with other agencies such as the Georgia Department of Agriculture, University of Georgia, U.S. Department of Agriculture Forest Service and the USDA Animal and Plant Health Inspection Service.

About half of Georgia's 24.7 million acres of forestland contain oak trees.


Resources