An Unwanted Pine Pest Revisited

Contact: Bob Trumbule, Maryland Department of Agriculture |

An Unwanted Pine Pest Revisited
Photo: Indiana Department of Natural Resources Archive, Indiana Department of Natural Resources,
An Unwanted Pine Pest Revisited
Photo: Beat Forster, Swiss Federal Institute for Forest, Snow and Landscape Research,

ANNAPOLIS, MD (November 4, 2010) – The pine shoot beetle, Tomicus piniperda, is a European invasive species that was inadvertently introduced into the Great Lakes Region of the U.S. and detected in 1992. This small bark beetle now occurs in 17 states including Maryland, Pennsylvania, West Virginia, and Virginia. The beetle’s detection has resulted in a federal domestic quarantine to regulate the movement of pine nursery stock, cut pine Christmas trees, pine greenery, and pine logs and bark products from areas where it is established. MDA has conducted surveys for pine shoot beetle since 1992 and first detected the beetle in Maryland in 1995. Based on 2010 results, pine shoot beetle has newly been detected in Baltimore, Carroll, Harford,and Howard counties, which now join Garrett, Allegany, Washington, Frederick, and Montgomery counties under state and federal quarantines for pine shoot beetle. The Maryland Invasive Species Council selected pine shoot beetle as the invader of the month in January of 2004 and, based on recent developments, is providing this updated version for November, 2010.

The pine shoot beetle is a pest of pine trees in North America that potentially could hurt production and trade of pine nursery stock, pine greenery, and pine logs in areas where it is detected. It is reported to be the second most destructive shoot-feeding species in Europe. It is also established in Asia. According to the 2007 Census of Agriculture for Maryland, there are more than 200 Christmas tree growers in the state with nearly 3,000 acres in production. This census also reported that in 2007 Maryland Christmas tree growers harvested 77,800 trees valued at $2.4 million. Maryland is on the leading southern edge of the federal pine shoot beetle quarantine, and the northern edge of the range of southern yellow pine, including Maryland’s loblolly pine resource valued at more than $440 million. Dimensional lumber and plywood products manufactured from southern yellow pine are used extensively in home construction in the United States.

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 which 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.

Pine shoot beetles apparently prefer Scotch pine but will feed on most pine species that have needles arranged in clusters of two and three. The beetles will not infest other conifers such as spruce and fir. Although this insect may have the potential to be a serious forest pest, most damage in North America has been reported from Christmas tree farms.

During the winter holiday season, evergreen trees such as pines become more important and visible to Marylanders but the pine shoot beetle remains largely unseen. The MDA, through trapping and visual surveys in cooperation with the USDA, looks for beetles and works with the nursery, logging and Christmas tree industries to inform them of the quarantine and methods of compliance in order to minimize potential risks of spread and to facilitate commerce and trade. In 2010, in addition to the four new county detections of pine shoot beetle, MDA inspectors have observed increased pine shoot beetle damage for the first time in established quarantined counties.

Federal and state quarantine regulations require the inspection of cut pine Christmas trees, pine nursery stock, pine logs, stumps, and lumber with bark attached, and pine bark mulch before these regulated articles can move out of quarantined areas. A federal permit is required for interstate movement. Lumber and logs without bark attached are not regulated.

The best defense against the pine shoot beetle is to employ effective integrated management practices throughout the production cycle of the trees to reduce beetle populations in host plants and growing areas. Management strategies include sanitation practices to remove infested material from growing fields, chemical controls to reduce shoot feeding by adults, and visual and trap surveys to monitor population levels. Growers should work with their state and/or federal regulatory officials to determine whether they are in an infested area, or are at risk of becoming infested, and to develop a management plan that is in compliance with state and federal regulatory requirements.

For more information regarding the Maryland Pine Shoot Beetle Program and movement of regulated articles within Maryland, contact the Maryland Department of Agriculture – Plant Protection and Weed Management Section, 410.841.5920.

For information regarding the USDA Pine Shoot Beetle Program and interstate movement of regulated articles, contact the USDA Animal Plant Health Inspection Service (APHIS) Plant Protection and Quarantine (PPQ) office in Baltimore, 410.631.0073.

For more information, please visit:

Maryland Department of Agriculture
USDA Forest Service

For more information about Invasive Species of Concern in Maryland, visit

photos available electronically on request.