Northern pitch twig moth, Petrova albicapitana,
 

Fig. 123 Northern pitch twig moth larvae feed singly within a nodule	Fig. 124 Girdling by northern pitch twig moth larva.	Fig. 125 Breakage and deformity caused by northern pitch twig moth attack.	Fig. 126 Northern pitch twig moth feeding often occurs near branch junctions. Trees are subsequently deformed and weakened.

Tree Species Attacked: Young lodgepole pine is attacked, generally trees from 0.3 to 3 m tall.

Insect Description & Damage Symptoms: The mature larvae are about 1.7 cm long. The colour of the body varies from yellow to orange-brown. The head is reddish-brown. Characteristic pitch nodules occur near terminal buds, the crotch of branch junctions, or at the crotch of the main stem and branches. These nodules consist of pitch and frass and conceal a single feeding larva in a silk-lined inner chamber. The nodules produced at branch or stem crotches are usually 2.0 cm or more in diameter and are formed by older larvae. Those occurring at terminal buds are usually less than 1 cm in diameter and are produced by newly emerged larvae. The adult moth is a mottled light brown and silver.

Damage: Feeding larvae can kill the tips of branches or terminal shoots by girdling the inner bark. Occasionally, the nodules on the main stem become large enough to kill the top of a tree. More typically, however, the damaged area is weakened and therefore subject to wind or snow breakage. In addition, larval feeding may reduce timber quality by inducing crooked leaders. Plantations are more heavily attacked than densely stocked, naturally regenerated stands. This insect rarely attacks suppressed trees.

Similar Damage:  On trees over 2 m in height, the sequoia pitch moth can cause similar damage where the two pitch moths overlap in distribution. The mature sequoia pitch moth larvae is larger and lighter in colour than the northern pitch twig moth larvae, and the sequoia pitch moth pitch mass tends to be larger and messier. The gouty pitch midge can cause similar deformities, but will not have the pitch mass associated with the pitch twig moth.

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Contact Tim Ebata if you have comments on the presentation of this information.

BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated February 18, 2002