Xeris spectrum (L.)From: Kolk A., Starzyk J. R., 1996: The Atlas of Forest Insect Pests Occurrence: Holarctic species widespread in Europe, the northern Africa, Siberia, Turkey, Japan and the North America. Host Plants: All conifers except yews, mainly the common fir, rarely the Norway spruce, Scots pine, larch and Douglas fir. Morphology: The body length of males is 12-28 mm, and females are 12-28 mm long. The body is shiny, black or brownish-black with whitish spots on head behind eyes and on sides of pronotum. The ovipositor is as long as body or longer. The legs of both sexes are yellowish-reddish, but males have brownish rings on tibiae. The egg is whitish, elongated, about 1mm long. The larva is slightly dorsoventrally flattened, up to 25 mm long. The pupa is 13-50 mm long with antennae extending beyond wings at the level of the eighth segment. Biology: Adults are active from late-June to early-July. Females oviposit to holes (1-9 eggs per hole) of 20-25 mm in depth drilled with ovipositor. A female lays about 100 eggs. Larvae excavate 6 mm wide tunnels in the wood. Larvae feed on the wood, and unlike other siricids no symbiosis with fungi has been recorded so far. Larvae often develop in the blue-stained wood. Tunnels are oval and filled with the wood dust. This species has one generation per 2 years, occasionally 3 or even 4 years. Damage: X. spectrum is an important technical pest of the fir timber, decreasing the value of the wood. It has a tendency to abundant occurrence in pure fir and mixed fir-spruce stands damaged by wind, fire, pathogenic fungi or snow. It attacks also trees wounded by games and during harvesting operations, as well as the timber and rarely stumps. Sporadically the larval density can reach 60 specimens per 1 m of the tree stem. Control: Similar to U. gigas.
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Forest Pests: Insects, Diseases & Other Damage Agents |
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