Forest Pests: Insects, Diseases & Other Damage Agents

Pissodes weevil - Pissodes pini (L.)

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: Europe, Siberia and the Caucasian Mountains.

Host plants: Mainly the Scots pine, eastern white pine and mountain pine, sporadically the spruce and larch.

Morphology: Adults are 6-9 mm long, dark brown or reddish, with 4 yellow spots on pronotum and two oblique stripes on elytrae. The larva is yellowish-white, with the light brown, oval head, legless, 14-16 mm long and 2.5-2.8 mm wide. The pupa is elongated, yellowish-white, with sharp end.

Biology: Overwintering occurs in the imaginal, larval or occasionally in pupal stage. Adults overwinter usually in litter or bark crevices. They emerge in late-April or early-May and start maturation feeding. After mating, females oviposit in clusters in holes made in the thick bark of the lower parts of trees. Oviposition with some pauses for regenerative feeding may last the entire season. After hatching, larvae bore galleries up to 20 cm in length in the phloem. Feeding galleries create star-like pattern. Pupal chambers with whitish wooden chips are constructed at the end of larval galleries. Larvae develop for about 2 months, and pupal development lasts about 2 weeks. Adults lifespan reaches 2 years.

Damage: P. pini infests only trees weakened by fire, pollution, defoliators or pathogenic fungi. Adults during supplementary feeding damage bark and cambium that causes oozing of resin droplets and thus trees look like sprayed with a lime. On the eastern white pine adults have supplementary feeding on the whole stem, while on the mountain pine they feed mainly on branches.

Preventive measures: Removal of windfalls, weakened trees and timber, particularly with the thick bark.

Control: Removal of infested trees. The use of trap trees is also recommended. These trees serve also as traps for Tomicus piniperda, Phaenops cyanea and Monochamus galloprovincialis. The use of traps special for P. pini like bolts with the thick bark are recommended too. Occasionally logs with the damaged bark also can be used. Trap trees and logs should be debarked before pupation. All stumps in clear cut areas with high infestation rates of P. pini should be debarked.

Diagram, Adult and galleries, Poland Image by Robert Dzwonkowski	Adult(s) Image by Stanislaw Kinelski
Galleries, High density larval galleries with pupal chambers Image by Stanislaw Kinelski	Larva(e) Image by Stanislaw Kinelski

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