Plants > Plant Pests > Common Pine Shoot Beetle  

Tomicus piniperda L. - Common Pine Shoot Beetle

Background

Tomicus piniperda L. is recognized as one of the most destructive bark beetles of pine in its native Eurasia. During the summer of 1992, the United States first reported finding this pest in a Scots pine (Pinus sylvestris L.) Christmas tree plantation near Cleveland, Ohio. By the end of 1992, the beetle had been reported from six states bordering on the Great Lakes. As a result of the American find surveys began in Canada in 1993 and by the end of the year established populations of T. piniperda had been found in seven counties in southwestern Ontario.

Host

Pine (Pinus) is the principle host tree for this pest. In the Great Lakes region T. piniperda has demonstrated a preference for Scots pine (Pinus sylvestris L.) but has also infected Red pine (P. resinosa L.), Jack pine (P. banksiana L.), Eastern white pine (P. strobus L.) and Austrian pine (P. nigra L.). When populations levels become elevated, adults have been reported to breed in logs of spruce (Picea spp.), fir (Abies spp.) and larch ( Larix spp.).

Distribution

• Asia: China, Japan.
• Europe: All countries
• North America: Canada (Ontario, Quebec); USA (IL, IN, OH, PA, MI, MD, ME, NH, NY, WI, WV, VA, VT ).

Biology

Pine shoot beetles complete only one generation per year. Adult beetles spend the winter under the bark at the base of living pine trees. When day temperatures reach 15° C in late March and April, the adults become active and tunnel out of the bark in search of suitable brood material ( dead trees, damaged trees and freshly cut stumps). Females can fly several kilometres in search of a suitable brood site. Once a site is located the female will mate and lay eggs in an egg gallery that she tunnels out between the inner bark and the cambium of the tree. The egg gallery may reach 25 centimetres in length. Larvae hatch from late April to June and feed in separate feeding galleries which radiate away from the egg gallery (figure 2.) Mature larvae pupate and emerge as adults between July and October. The new adult beetles fly to the tops of pine trees to begin maturation feeding within the shoots (figure 3.). During this process the adult may damage between two and six shoots (figure 4.). This is the most destructive stage of the life cycle with damaged shoots turning yellow, drooping and eventually falling off the tree. Trees of all sizes are attacked. In late October to November the adult beetles move down the tree to the base of the trunk where they bore into the bark to over winter.

Detection & Identification

Symptoms

Damaged shoots will display a round entrance hole usually surrounded by pitch (figure 3.). The shoot may have one hollowed tunnel or several short hollow tunnels. The damaged shoots will turn yellow, droop (a process known as flagging) and eventually fall off the tree (figure 5.).

Identification

The adult beetle is 3 to 5 millimetres in length, cylindrical, brown turning to shiny black (figure 1.). The larvae are legless, up to 5 millimetres in length, having a white body with a brown head.

Figure 1.	Figure 2.	Figure 3.
Figure 4	Figure 5.

Text : Plant Health Surveillance Unit
Images: Deborah McCullough, Michigan State University, Dept. of Entomology and Forestry, East Lansing, Michigan, USA.