Six-toothed bark beetle - Ips sexdentatus (Börn.)From: Kolk A., Starzyk J. R., 1996: The Atlas of Forest Insect Pests Occurrence: Europe, the northern Asia to Korea. Host plants: The Scots pine and other pine species, sporadically the Norway spruce and larch. Morphology: It is the second biggest bark beetle in Poland. Adults are 5-8 mm long, cylindrical, robust, brown or brownish-black, shiny and haired. Elytral declivity of both males and females is with 6 teeth on each margin side. The 4th tooth is the biggest, sharp and club-like on its top. Biology: Adults overwinter in litter or under the bark of old pines. Occasionally overwintering may occur in larval or pupal stage in galleries. This species has one or two generations per year and sister generation, depending on the weather conditions. Adults of the first generation fly in April-May, and those of the second generation - in July-August. Males prepare nuptial chambers of 4-5 mm in width under the thick bark of standing or fallen trees and attract usually 3, rarely 2, 4 or 6 females. Female construct egg galleries of up to 50 cm in length and 5 mm in width. They go along fibers and usually one gallery is directed up and two other - down. In each gallery females chew 3-4 ventilation holes and then lay about 60-70 eggs singly in cut niches. Larval galleries are irregular. They pupate in oval chambers constructed deeply in the bark. The newly-formed beetles have maturation feeding under the bark. The feeding galleries have horn-like pattern. Damage: It is a typical secondary pest of the Scots pine. It usually attacks weakened standing or fallen, wind broken trees and the timber with the thick bark. Attacked trees can be easily recognized by whitish-brown shredded wood and bark or resin flows visible on the bark of the lower part of trees. This species is active in timber yards, where high amount of logs with the bark is available, and in stands with the timber remained there after summer harvesting. The timber of attacked trees can be easily infested with the blue-stain fungi. In France and some other countries of Europe, this species can attack also healthy or slightly weakened trees, thus becoming more serious than Tomicus piniperda. Preventive measures: Removal of all potential breeding materials (timber, weakened trees, windthrows, etc.) from woodlands in the period from October through March. Control:
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Forest Pests: Insects, Diseases & Other Damage Agents |
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