Sawflies are a group of insects (suborder Symphyta) of the Hymenoptera (bees, ants and wasps). There are about 500 species of

Sawfly are small winged insects, related to bees, wasps and ants. Their caterpillar-like larvae feed on the leaves or fruits of certain plants, including apples, gooseberries and Solomen’s seal.

Seen berberis sawfly? We would like to know.

As part of our research, the RHS would like to know where berberis sawfly has been seen.

Please submit your records via our berberis sawfly survey (expected time to complete survey = two minutes).

A map of distribution is given in the gallery below. Watch an animated map of the results from the berberis sawfly survey (links to YouTube).

Thank you to everyone who has submitted records so far. Discover other sightings you can report to help our research here.

• Branches or occasionally the whole plant can be defoliated – berberis sawfly is the only insect likely to cause such severe defoliation to Berberis or Mahonia
• On inspection, black-headed, creamy white caterpillar-like larvae with black spots and orange yellow blotches may be seen feeding on the foliage
• The adults are shiny black insects, up to 8mm long, with greyish-black wings. They appear similar to many other species of sawfly
• Sawfly larvae on plants other than Berberis or Mahonia will be a different species. 

Sawflies can be a part of the biodiversity a heathy garden supports.

• Where possible, tolerate populations of sawfly – plants usually recover from defoliation 
• Encourage predators and other natural enemies of sawfly in the garden, such as birds, wasps and ground beetles
• Check Berberis and Mahonia frequently from the end of May for the presence of larvae to prevent a damaging population from developing
• Remove larvae by hand if required and where practical

There are two generations of berberis sawfly during the summer and there may be a third generation in autumn.

The adult sawflies are 7-9mm long and are shiny black with darkened wings and antennae that are swept upwards.

Eggs are inserted under the epidermis on the underside of leaves of host plants, in batches of up to seven. These hatch into caterpillar-like larvae that proceed to devour the foliage. When fully grown, the larvae are up to 18mm long. They go into the soil to pupate within silk cocoons. This insect overwinters in the ground as pupae.