Pissodes picae
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: Widespread in the mountain regions where stands of the common fir are present. It is distributed from the northern Caucasian Mountains through the European part of Russia to the central and southern Europe and Spain.
Host plants: Mostly the common fir, but also other species of a fir, like Caucasian fir, Douglas fir and others.
Morphology: The body is narrow, brownish-red, 5-10.5 mm long. Elytrae are with punctures of different sizes and depths in two rows separated by ridges. On elytrae two yellow stripes separated on suture of small scales are present. Pronotum is bell-shaped with spine-like basal corners. The hind stripe is usually much more distinct than anterior one. The latter one can be reduced even to two spots. The egg is white, elongated, 3.5 x 1.2 mm in size. The larva is whitish, up to 14-16 mm long with the reddish-brown head. The pupa is 11 mm long and covered with distinct spines.
Biology: Adults are active from April to the second half of August with the culmination in spring. Newly hatched adults overwinter in the litter or pupal cells, and in spring of the next year have supplementary feeding on young fir trees, occasionally on the timber. During feeding they chew through the cambium to the sapwood that stimulates a flow of resin and decline of attacked trees. Females lay eggs in clusters in holes chewed in the bark. Larval galleries run from the center to different directions and reach up to 70 cm in length and 2.5-9.5 mm in width on big trees. Galleries are filled with dark brownish frass. In the end of the gallery, the larva excavates the pupal chamber of 7x3 - 29x12 mm in size surrounded by white long fibres. The pupal stage lasts 3 weeks. This species has one generation per year, in the mountains - one generation per two years.
Damage: P. picae attacks mainly weakened trees, but when abundant, it becomes more aggressive and can infest healthy trees. Characteristic sap flow ("white stems") and fading needles indicate infested trees. It attacks mainly trees inside even-aged fir monocultures. Sometimes a few larval galleries encircling the stem are enough to kill a tree.
Preventive measures and control: Planting of forest stands diverse in a structure and species composition. Cutting and removing of infested trees and residues like thick branches and tops before the adults emergence, that is before the end of March. The use of trap trees from April 15th in lowlands to May 15th: one group of 2-3 trees per ha in forest openings up to 2 ha in size, two groups in openings up to 4 ha in size, 1 group per 200 m on forest edges. Trap trees should not be pruned and placed in semi-shady places. It is recommended to make wounds on trees that increases attractiveness of traps. Traps should be debarked in late-June or early-July, before larvae pupate.
 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 |
