Join the RHS today and support our charitable work
Keep track of your plants with reminders & care tips – all to help you grow successfully
RHS members get reduced ticket prices
RHS members get free access to RHS Gardens
Free entry to RHS members at selected times »
Reduced prices on RHS Garden courses and workshops
020 3176 5800
Mon – Fri | 9am – 5pm
Help us achieve our goals
Join the RHS today and support our charity
The larval stage of Solomon’s seal sawfly can completely defoliate Polygonatum species and hybrids in early summer.
Solomon's seal sawfly
Sawflies are in the same group of insects as bees, ants and wasps (the Hymenoptera). They have caterpillar like larvae that feed on plants the adults are winged insects that can appear fly-like. The larvae of Solomon's seal sawfly feed on the leaves of Polygonatum.
Solomon's seal sawfly larvae feed in large groups so defoliation can occur very quickly. Keep vigilant for early signs;
Whilst the defoliation caused by the sawfly larvae can appear severe it normally occurs after flowering and the plants will usually put on healthy growth in the year following an attack. Therefore this insect can be tolerated and the plants will survive.
Search for the larvae and remove them from the underside of leaves.
Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)
Adult Solomon’s seal sawfly are black-bodied insects, 8-9mm long, with two pairs of blackish grey wings. In appearance they are similar to medium sized flies but are in the same group of insects as the bees, ants and wasps, the Hymenoptera. They emerge in late spring at about the time when their host plant is coming into flower.
The female uses her saw-like eggs-laying organ to insert rows of eggs into the leaf stems. This causes vertical purplish brown scars to develop where the eggs were inserted.
The larvae feed together in small groups on the underside of the leaves. Initially they make small elongate holes but as the larvae increase in size, their appetite also increases. By mid-summer, the stems may have been stripped of foliage.
The fully fed larvae go into the soil where they overwinter and pupate in the following spring. Defoliated plants will survive but may produce reduced growth in the following year.
Chemical labels explained
Chemicals: using a sprayer
Chemicals: using safely and effectively
Large rose sawfly
Rose leaf-rolling sawfly
Rose slug sawfly or slugworm
Social pear sawfly
the RHS today and get 12 months for the price of 9
RHS members can get exclusive individual advice from the RHS Gardening Advice team.
We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.