Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001736
11/12/99
Mountain Ash Sawfly
The mountain ash sawfly attacks only European or American
mountain ash. The insect overwinters as a pupa. The
adults emerge in late May to early June and mate. The
female lays eggs near the leaf margins with the larvae
hatching in early June. The larvae (Vis. 1) feed on the
leaves for two to three weeks and then drop the ground to
form a cocoon. A second generation may occur.
The insects feed in colonies. The very young larvae only
skeletonize the leaves but later eat the entire leaf down
to the mid vein. When all the leaves on one branch are
eaten they move to another.
The larvae are greenish at first become yellowish white
with black spots as they mature.
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This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
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