Black spruce long-horn beetle-Tetropium castaneum(L.) and Brown spruce long-horn beetle-Tetropium fuscum fabr.
From Bugwoodwiki
From: Kolk A., Starzyk J. R., 1996: The Atlas of Forest Insect Pests (Atlas skodliwych owadów lesnych) - Multico Warszawa, 705 pages. Original publication in Polish. English translation provided by Dr. Lidia Sukovata and others under agreement with The Polish Forest Research Institute.
Occurrence: Both species throughout the central and northern Europe and Siberia. T. castaneum occurs also in the northern part of the Caucasian Mountains, the northern Japan, Korea, Sakhalin and Mongolia. T. fuscum is spread also in the mountains of the southern Europe.
Host plants: T. castaneum prefers the Norway spruce, but also occurs on the Scots pine, rarely on larch and fir. In Poland it was also recorded on exotic tree species like the Douglas fir, eastern white pine and Sitka spruce. T. fuscum prefers both the Scots pine and Norway spruce, occasionally attacks the fir, Douglas fir, eastern white pine and Sitka spruce
Morphology: Adults of both species are black, 8 up to 19 mm long. Pronotum of T. castaneum is shiny, with sparse punctures. The color of elytrae, pronotum, legs and antennae varies from black to reddish. Pronotum of T. fuscum is dull, with dense punctures. The colors are similar to T. castaneum, but elytrae at the basal part are covered with dense yellowish pubescence creating a wide band across. Eggs of T. castaneum are white, oval, 1-1.2 mm long. Eggs of T. fuscum are elongated, slightly engraved on both ends, 1.4x0.4 mm in size. Larvae are pupae of both species are rather similar with some different details in body structure.
Biology: Adults of T. castaneum fly from May through September, with a peak in June-July. Adults of T. fuscum are active in June through August. Biology and life cycles of both species are similar. Adults do not feed. Females oviposit singly into bark crevices. Larvae hatch 10-14 days later and bore to the phloem and cambium. Larvae feed under the bark and upper wood making galleries up to 2 cm wide, which are filled first with brown shredded bark, then with white shredded wood. Larvae molt 4 times and in autumn bore tunnels of 7x4 mm in size into the wood in depth of 2-5 cm, where pupate in pupal chambers. Larval galleries and pupal chambers of both species are similar. Pupation occurs from early-May through late-June. Adults emerge several days after pupation through oval holes of about 7 mm in diameter. Both species have one generation per one or two years.
Damage: Both species are very important secondary pests of pine and spruce forests. They attack and often kill weakened trees. Technical damage is made by constructing of pupal chambers. Infested trees are can be easily recognized in early autumn by signs of woodpecker activity. In spring next year trees fade.
Preventive measures and control: Restrictions concerning the presence of weakened trees in the forest. Infested trees should be cut and debarked. The use of trap trees is recommended in high density populations. Trap trees (1-3 per ha) should be established by mid-May. They should be checked in June and July and debarked when larvae are still feeding under the bark, before they bore into the wood, usually in late-July. Trap trees for I. typographus in spruce stands, and for Paenops cyanea and Monochamus galloprovincialis in pine stands are also used as traps for Tetropium spp.
 Photo by Robert Dzwonkowski, , Bugwood.org |  Photo by Stanislaw Kinelski, , Bugwood.org |
 Photo by Stanislaw Kinelski, , Bugwood.org |  Photo by Stanislaw Kinelski, , Bugwood.org |
 Photo by Stanislaw Kinelski, , Bugwood.org |  Photo by Stanislaw Kinelski, , Bugwood.org |
 Photo by Stanislaw Kinelski, , Bugwood.org |  Photo by Stanislaw Kinelski, , Bugwood.org |
 Photo by Stanislaw Kinelski, , Bugwood.org |
