Sawflies
Sawflies are named for the adult female's sawlike abdominal appendage used for inserting eggs in foliage.
Adults have two pairs of wings and are dark, wasplike, somewhat flattened insects, usually 0.5 inch long
or shorter. Some species mine leaves or stems. Most exposed-feeding larvae have six or more prolegs on
the abdomen and one large "eye" on each side of
the head. Sawflies include species that feed openly on foliage
and those that mine inside stems and leaves.
Identification
of species | Life
cycle
Damage
Most conifer sawflies chew needles or buds; a few mine in shoots and cause tip dieback. Broadleaf-feeding
species may skeletonize or chew holes in leaves or mine tissue, causing winding, discolored tunnels. Different
species roll leaves, web foliage, or cause plant galls. Some may feed in stems, causing wilting. Sawflies in
forests in the western states can retard plant growth and occasionally kill trees in landscapes if populations
are high.
Solutions
Trees and shrubs tolerate moderate defoliation. Prune damaged foliage and stems. Parasitic
wasps, predaceous beetles, or fungal and viral diseases commonly kill sawfly populations. Avoid broad-spectrum
insecticides because of their adverse effect on natural enemies.
Insecticidal soap or narrow-range oil kill
exposed-feeding sawfly larvae but may damage blossoms. Pear
sawfly larvae can sometimes be washed off plants with a forceful
stream of water.
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Pear sawfly larva
Skeletonized leaves caused by bristly roseslug
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