Plants Test Positive for Sudden Oak Death
MDA Takes Action, Seeks Consumer Assistance
ANNAPOLIS, MD (May 7, 2004) - Federal and state agriculture officials are asking for the public's help in containing a fungus-like plant disease that could wreak havoc on state's nursery industry and forests.
Phytophthora ramorum, also known as sudden oak death, is a fungus-like disease that causes leaf spots, cankers and dieback in plants, trees and other shrubbery but poses no threat to people. The disease can spread many ways including in the air, on water, or by people.
"The presence of sudden oak death is a very serious matter, and we are asking for the public's help in containing its spread and potentially devastating effects," said Dr. William F. Gimpel, Jr., MDA Administrator of Plant Protection and Weed Management. "We are asking anyone who purchased camellias, viburnum, or lilacs from Maryland businesses or by mail in the past 12 months to contact the University of Maryland's Home and Garden Information Center hotline at 1-800-342-2507. However, we believe that nursery stock currently available for sale in Maryland is of excellent quality, so Mother's Day buying should not be a concern."
The U.S. Department of Agriculture confirmed a positive identification on April 30 from a composite sample of the disease collected by MDA from a common garden Rhododendron at a retail nursery in Maryland. The MDA found the diseased plant as part of an aggressive survey of a broad range of representative nursery and retail outlets that are known to carry the host materials. Additionally, MDA is working with the U. S. Department of Agriculture's Animal and Plant Health Inspection Service (USDA-APHIS) to determine if the infection has spread and to identify the source of the infected plants.
Maryland is one of 39 states known to have received potentially infected plants from two California nurseries, Specialty Plants, Inc. of San Marcos, Calif. and Monrovia Nurseries of Azusa, Calif, in the past 12 months. The agency continues its investigations tracing potentially infected plants shipped into Maryland.
The MDA has contacted more than 200 individuals in Maryland who received potentially infected bonsai camellia plants from Specialty Plants, Inc., which is a mail order company, and has requested leaf samples from those plants. Over half of those individuals have responded. Only one of the 95 plants from Specialty Plants tested to date is a suspect positive, pending USDA-APHIS confirmation.
The MDA has also completed visits to all Maryland establishments that received shipments of potentially infected P. ramorum host plants in the past year from Monrovia Nurseries. Of the 500 plants shipped to area businesses, fewer than 50 remained unsold and in stock. The MDA placed holds on certain nursery stock received from the Monrovia while agency inspectors and plant pathologists sampled and tested host material. Plants testing negative for P. ramorum have been released by MDA for sale. The MDA has detected one suspect positive sample from Monrovia, which has been sent to USDA-APHIS for confirmation. The MDA will conduct long-term surveys to monitor for P. ramorum in nurseries and the environment.
"Because of the numerous known hosts in Maryland's native forests, the release of sudden oak death into the state's forests has the potential to kill thousands of trees, changing our forests forever," said Jeff Horan, Chief of Forest Resource Planning for the Maryland Department of Natural Resources Forest Service.
Additionally, anyone with a plant listed on the P. ramorum host or associated host list purchased during the same timeframe that is showing unusual symptoms should contact the Home and Garden hotline for more information and assistance.
USDA-APHIS has restricted movement of nursery stock from all California nurseries outside of the already quarantined counties in the state. California nursery owners who want to ship listed plants must undergo a nursery stock inspection before those plants can be transported across state lines. The new measure prohibits an estimated 1,500 California nurseries from shipping plants susceptible to P. ramorum until those nurseries can be inspected and found free of the pathogen.
P. ramorum first appeared in California in 1995 and has since been found in Oregon, Washington and British Columbia. This disease attacks at least 59 host plant species, including Douglas fir, oak, western starflower, rhododendron, lilac, mountain laurel, camellia and viburnum. Although the disease has killed thousands of oak trees in California, many other hosts are not killed.
The greenhouse and nursery industry is Maryland's second largest agricultural sector with total gross receipts from horticulture crops and landscaping in 2000 of $1.15 billion. Retail sales accounted for over two-thirds of receipts, with a total value of $781 million (Maryland Agriculture Statistics Service "Green Industry" survey, 2001).
To report possibly infected plants or for more information, contact the Maryland Home and Garden Information Center at 1-800-342-2507 or visit www.agnr.umd.edu/users/hgic. Information is also available by logging onto www.mda.state.md.us (click on P.ramorum, "Sudden Oak Death" Information).
Posted May 7, 2004