How to recognise it
The adults are up to 10mm long, have two pairs of wings and are usually a dark colour, often mistaken for flying ants.
Symptoms of an infestation can include leaves being mined, the appearance of galls and leaves curling.
Reproduction may be sexual or parthenogenetic, depending on whether the species produces sufficient males. The female uses her ‘ovipositor’ (a saw-like device from which the common name of ’sawfly’ is derived) to pierce soft plant tissues and lay eggs in them. The resulting larvae can be distinguished from caterpillars by having at least six pairs of fleshy prolegs (along their abdomen) whereas caterpillars have only 4 or 5 pairs.
Why it’s a problem
While the adults mainly feed on pollen or are carnivorous, the larvae are more problematic to the gardener as they feed on leaves and other soft, above ground plant parts.
Where you are likely to find it
There are a wide range of sawflies, each attacking different species of plants including apples, plums, pears, cherries, gooseberries, roses, Solomon’s seal, irises, willows, pines, hazels and aquilegias.
How to deter it
Many species overwinter in the soil (as larvae or eggs), so winter digging around susceptible plants can expose them to the cold and kill them.
How to get rid of it
Most species can be dealt with using a contact insecticide, if the extent of the infestation requires it. Additional treatment may be appropriate for specific species of sawfly.
Is it good for anything?!
Other useful information
Many hundreds of different types of sawfly cause problems in the garden. We have additional information on the following species: