Pityokteines curvidens
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: The European species, widespread in the whole range of the common fir distribution.
Host plants: Exclusively on the common fir, in mixed stands with fir sporadically on Norway spruce, Scots pine and larch.
Morphology: Males of this bark beetle are 2.7-3.2 mm long, and females are 2.0-2.6 long. P. kurvidens is similar to P. spinidens and P. vorontzovi. The body is cylindrical, shiny, brown, covered with dense hair. Elytrae are with rows of punctures. The elytral declivity is with 3 teeth and 2 granules. The first tooth on the elytral declivity of males is pointed upward, two other teeth are hook-like and bended towards each other. Females have small teeth. Hair on pronotum is only slightly longer than on frons. Eggs are small, whitish. The larva is up to 8 mm long.
Biology: P. kurvidens is a polygamous species having two generations per year. Adults of the first generation are active from the end of April through May in lowlands, and mainly in May in the mountains. The second generation is active in July and August. Males excavate nuptial chambers, from which females excavate two maternal galleries upward and downward. Later these galleries are divided into two arms to the right and to the left. Maternal galleries are about 5-10 cm long and 1 mm wide. They are mostly in the bark, but also visible on the wood. While excavating galleries, brownish frass is removed outside. Larvae hatch 2 weeks after and start to excavate galleries up to 7 cm long along fibres in the bark first, and later in sapwood. After 4-5 weeks of feeding, larvae prepare pupal chambers. They are 2-10 mm deep, closed with white frass. Two-three weeks later adults hatch and start to feed on the surface between the bark and sapwood. Adults emerge through oval exit holes of about 2mm in diameter. The occurrence of the sister generation depends on the weather conditions.
Damage: One of the most dangerous pests of fir. It can kill trees weakened by various factors. It also infests the timber, windthrows etc. It develops mainly in the lower part of the stem. High density populations can attack healthy trees.
Preventive measures: Rapid utilization and/or removal of cut timber and dying trees (with damaged crowns) from woodlands during winter.
Control: Utilization or removal of infested trees. When large numbers of trees require storage, they may be debarked. Trap trees are also recommended. They should be debarked before larvae entered the wood.
 Photo by Robert Dzwonkowski, , Bugwood.org |  Photo by Stanislaw Kinelski, , Bugwood.org |
 Photo by Stanislaw Kinelski, , Bugwood.org |  Photo by Stanislaw Kinelski, , Bugwood.org |
