Unwelcome Pest “Needles” Maryland Nursery, Logging and Christmas Tree Industries
Pine Shoot Beetle

Contact: Robert F. Trumbule, Maryland Department of Agriculture
301-927-8355

ANNAPOLIS, MD (January 2004) - The Maryland Invasive Species Council, the group that last year taught state residents about the importance of controlling and eradicating unwelcome intruders such as giant hogweed, fire ants, and garlic mustard, launches its 2004 “invader of the month” campaign with the pine shoot beetle. The pine shoot beetle, Tomicus piniperda, is a potentially severe pest of pine trees in North America that could hurt production and trade of pine nursery stock, greenery, and pine logs in areas where it is detected.

“During the winter months evergreen trees such as pines become more important and visible to Marylanders but the pine shoot beetle remains largely unseen,” said Robert Trumbule, the entomologist with the Maryland Department of Agriculture (MDA) responsible for coordinating the pine shoot beetle management program. “It is our job to look for the beetle and to work with the nursery, logging and Christmas tree industries, to make sure that trees produced in Maryland are free of the pest.

The pine shoot beetle is a European species that was inadvertently introduced into the Great Lakes Region and discovered in 1992. Since that time, this pest has been found in 12 states. Most of the beetle finds have been at Christmas tree farms and pine tree nurseries. The beetle’s detection has resulted in a federal domestic quarantine to regulate the movement of pine nursery stock, cut pine Christmas trees, greenery, and pine logs from areas where it is established.

Before regulated products can be shipped to areas free of pine shoot beetle, tree growing sites must be surveyed and found free of the insect. Maryland Department of Agriculture surveys first detected the pine shoot beetle in Maryland in 1995. The insect pest has since been found in Garrett, Allegany, Washington, Frederick, and Montgomery counties.

Adult pine shoot beetles spend the winter in the thick bark at the base of living pine trees. In late winter to early spring, beetles fly to pine stumps, logs or weakened trees where they bore through the bark and lay eggs. Larvae feed between the inner bark and outer sapwood for several weeks before they mature into adults. By early summer, the new generation of adults emerges and flies to the shoots of healthy pines. Beetles bore into and hollow-out the centers of shoots. Infested shoots become discolored, die, and often hang from the branch ends of infested trees for several months. This is the most noticeable and possibly most destructive phase of the beetle’s life cycle.

The beetle prefers Scotch pine but will feed on most species of pine that have needles arranged in cluster s of two and three. White pines are not attacked, and the beetles will not infest spruces and firs. Although pine shoot beetles have the potential to be serious forest pests, most damage in North America has been reported from Christmas tree farms.

The MDA staff, in cooperation with the U.S. Department of Agriculture’s Plant Protection and Quarantine officers, work with the nursery, Christmas tree, and logging industries in Western Maryland to inform them of the quarantine and methods of compliance in order to minimize potential risks and to facilitate commerce and trade. Trapping and/or visual inspections are conducted at all nurseries and tree farms that request certification of Christmas trees and pine products within the quarantine area, and at pine production plantations and log marshalling yards throughout the state. The MDA’s Plant Protection and Forest Pest Management staff make it possible for growers to prove compliance with federal law and to continue shipping pine trees and pine products from the quarantine area in Western Maryland.

The 1997 Census of Agriculture ranked the Maryland Christmas tree industry 18th in the nation for number of farms (292) and acreage (1419). The census reported that state growers sold approximately 209,000 trees for about $2.5 million.

photo: Natural Resources Canada
photos available electronically on request