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Berberis sawfly became established in south-east England in about 2000. It has since spread throughout most of England. It is the only insect that feeds on Berberis, likely to cause severe defoliation.
Berberis sawfly larvae.
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.
Berberis sawfly has creamy white, spotted larvae with black heads. They feed on the foliage of Berberis and Mahonia and can cause severe defoliation. This species of sawfly will only feed on these two plants.
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).
Submissions to our pest and disease surveys are stored permanently in an anonymised form in order to monitor the spread of the pest or disease. We may contact you within 2 months of your submission in order to verify your sighting but your personal data will not be permanently stored in connection with your submission and will be deleted after 1 year. We publish and share only non-identifiable data from survey submissions (such as a six figure grid reference) with third parties and the public for the purposes of scientific research and advancing understanding among gardeners.
Thank you to everyone who has submitted records so far – read a blog about the surveys
Watch an animated map of the results from the berberis sawfly survey (links to YouTube)
Plants with by berberis sawfly are easy to spot:
Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)
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. The antennae are swept upwards.
Eggs are inserted under the epidermis on the underside of leaves 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.
Chemical labels explained
Chemicals: using a sprayer
Chemicals: using safely and effectively
Large rose sawfly
Rose leaf-rolling sawfly
Rose slug sawfly or slugworm
Shrubs: pruning evergreens
Social pear sawfly
Solomon's seal sawfly
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