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Solomon's Seal Sawfly

Phymatocera aterrima

Solomon's Seal Sawfly

A close up of a Phymatocera aterrima Solomon’s seal sawfly on a leaf
Solomon's Seal Sawfly is an insect closely related to wasps, however, is lacking the characteristic wasp-waist. They belong to the largest family that's widely known by the common sawflies (Tenthredinidae). As the name suggests, the larvae of this sawfly feed on a plant that goes by the common name of Solomon's seal (Polygonatum). The larvae of this sawfly feed gregariously, meaning in large numbers all at once! For this reason, they can severely defoliate plants in a short space of time.


These sawfly can defoliate plants quickly.
These sawfly larvae possess many natural enemies including parasitic wasps and birds.


Adults: The adults are seldom seen. They look like large, slender flies. They're black-bodied with some black clouding on the wings. They grow to around 1cm. These should be present from May to June. When laying her eggs, a female will leave behind a purple-ish brown scar on the undersides of leaves. Larvae: Grey-white caterpillar-larvae may begin to become evident on plants from May to June. Larvae show similarities to caterpillars. They aggregate beneath the leaves of plants where they initially eat long strips from the leaf but eventually will consume the whole thing. These can grow up to 2cm. Eggs: Eggs are inserted within the stems and leaves.


Grey-white caterpillar-larvae with black heads may be seen in numbers beneath the leaves of Solomon's seal. Leaves of the infested plant may be completely defoliated.












Biological treatment

Plants almost always recover from defoliation. This insect should be tolerated. These larvae can be removed by hand and disposed of, or left on an elevated surface for the birds. Attract natural garden predators into the garden by providing spots of cover. Wild patches and strips of native wildflower/ grass can provide cover for predatory insects. Climbing plants such as ivy is excellent habitat for small songbirds. Likewise, bird tables and ponds are an excellent resource for attracting wildlife.

Chemical treatment

These insects don't affect the long term health of plants so it's not thought chemicals are necessary.


Solomons Seal

Polygonatum spp.

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