Silver Fir Beetle Biological Control

Pseudohylesinus sericeus (Mannerheim)

From: Bellows, Thomas S. ,Carol Meisenbacher, and Richard C. Reardon, 1998, Biological Control of Arthropod Forest Pests of the Western United States: A Review and Recommendations, USDA, FS, FHTET-96-21.

Origin: North America.

Range in North America: Alaska, British Columbia, California, Idaho, Montana, Oregon, Washington.

Plant hosts and damage: Abies spp., Tsuga heterophylla, Pseudotsuga menziesii. Adults bore into the bark, and excavate egg galleries between the bark and wood, where the larvae then feed. Attack is usually on windthrown, felled, injured or weakened trees. Extensive attacks can kill otherwise healthy trees.

Natural Enemies: Only one report (McGheney and Nagel 1969) idnetifies natural enemies of this species (Table 9).

Table 9. Natural enemies reported from Pseudohylesinus sericeus (after McGheney and Nagel 1969)

Pest Status: This beetle generally attacks predisposed or weakened trees. However, during 1947-1958 this beetle, together with Pseudohylesinus granulatus, killed 528 million board feet of commercial grade Pacific silver fir, mostly in Washington (Thomas and Wright 1961). It has also attacked young-growth stands of Tsuga heterophylla (McGheney and Nagel 1969).

Biological Control: Little is known of the natural enemies of this species. McGheney and Nagel (1969) reported parasitism by Cecidostiba acuta as a likely major mortality factor. Woodpeckers have also been reported feeding on this species (Thomas and Wright 1961). No diseases are reported.

Recommendations: This beetle has a demonstrated potential for serious infestations of firs. Out knowledge of its population biology is limited, and further studies of its ecology, particularly with reference to the role of natural enemies, and its host-plant relationships, are necessary before recommendations can be made.

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