Forest Pests: Insects, Diseases & Other Damage Agents

Cryphalus picae (Ratz.)

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 southern and central Europe, the western Ukraine, the southern Byelorussia, Lithuania, Turkey and Algeria.

Host plants: Almost exclusively the common fir, but sporadically also on the Norway spruce, Scots pine, larch and Douglas-fir.

Morphology: Adults are 1.1-1.9 mm long, similar to C. abietis, but differs in the setae size and pattern on elytrae. The body is robust, oval, dark brownish. Pronotum in the anterior part covered with rows of granules. Elytrae dull covered with scales and long hair well seen on top and declivity. The egg is white, oval, 0.5-0.8 mm long. The larva is white, 2.1-3.0 mm in length.

Biology: C. picae is a monogamous species with one generation per year in the mountains and two in lowlands. Adults are active in April, May and July, August. The nuptial chamber of about 0.5 cm in length is made by both sexes in the sapwood. While excavating, adults remove brownish frass outside. Females deposit eggs in clusters. A female lays 20 up to 40 eggs. After hatching, larvae excavate 2-4 cm long galleries in all directions from the nuptial chamber. Larvae feed 4-5 weeks, and then prepare the pupal chamber in the bark and upper layers of the sapwood. Adults emerge through the exit hole of 0.5-0.9 mm in diameter. Larvae or pupae overwinter in galleries, adults overwinter in short tunnels made in branches of old trees that lead to cancer-like deformations. Sometimes adults overwinter in the litter.

Damage: C. picae is a serious pest of firs, particularly in young stands. It attacks mainly weakened trees, windthrows and snags. C. picae prefers 20-60 year old trees. It can infest also young trees and tops or branches of old ones.

Preventive measures: Cutting and removal of weakened trees during winter and early spring. During thinning operations, harvesting of weakened and broken trees is recommended.

Control: Cutting and removal of infested trees in spring and summer. At high density populations the use of trap trees (possibly tops or thicker branches) is recommended.

Diagram, Adult and galleries, Poland Image by Robert Dzwonkowski	Habitat, Typical fir stand preferred by this species Image by Stanislaw Kinelski
Damage, Exit holes Image by Stanislaw Kinelski	Damage, To top of old fir tree Image by Stanislaw Kinelski
Adult(s) Image by Stanislaw Kinelski	Galleries Image by Stanislaw Kinelski
Galleries Image by Stanislaw Kinelski	Adult(s), In mating chamber Image by Stanislaw Kinelski

[ Contents ]     [ Previous ]     [ Next ]     [ Home ]