Woolly alder sawfly, Eriocampa ovata
   

Fig. 342   Woolly alder sawfly larva.	Fig. 343  Damage caused by woolly alder sawfly.

TREE SPECIES ATTACKED: Red alder is attacked on the coast. Other alder species are also attacked.

WHAT TO LOOK FOR: Skeletonized leaves and sawfly larvae covered with a white woolly secretion, or white molted skins on branches of damaged trees.

INSECT DESCRIPTION & DAMAGE SYMPTOMS: Larvae have greyish heads and pale green bodies, both of which are covered with a white, woolly secretion. They are 1.3 cm long when mature. Adults emerge from late May to July, and females lay their eggs along the main vein of the leaves. Larvae consume the whole leaf except the major veins. They spin cocoons in the soil, duff, or wood where they overwinter as pre-pupae. Some larvae, however, spin cocoons and continue to develop to the adult stage to produce a second generation.

DAMAGE: Damage can be severe on young alder seedlings and saplings. However, the current year's apical growth is usually untouched. On older trees, damage is usually inconsequential.

SIMILAR DAMAGE: Damage may be similar to that caused by the striped alder sawfly. The larvae will help in determining which species is responsible for the damage. Leaves skeletonized by leaf beetles, however, will have even the smallest veins remaining.

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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 19, 2002