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What’s eating my berberis leaves – All about Berberis sawfly and how to treat it
Last Updated on March 12, 2020 by John
If you have a barberry shrub or berberis as they are also known and you suddenly noticed that the leaves have been eaten away leaving almost nothing in its wake, you might wonder what’s eating your berberis leaves. Thankfully, sort of, there is only one culprit: the berberis sawfly.
The berberis sawfly made its way to England around the year 2000 and since that time it has spread quickly. It is important to keep your eyes peeled for it because it is the only insect that feeds on the berberis plant and more importantly, it can lead to severe defoliation in a short amount of time.
- Name: Berberis sawfly
- Plants affected: berberis, especially B. thunbergii
- Symptoms: leaves are eaten by larvae that are caterpillar-like. Plants can quickly become defoliated.
- Cause: larvae of the sawfly
- Time: between May and October
What is the sawfly?
The sawfly falls under the same group of insects as wasps, bees, and ants. They have larvae that are very much like a caterpillar in general size and appearance as shown in the picture above. These larvae feed on the plants and once they have eaten everything that your plant has worked so hard to grow the adults turn into winged insects that can fly like in the picture below.
They have white, spotted larvae that have blackheads. They will feed on the foliage and cause severe defoliation almost instantly. They only feed on the Mahonia and the berberis plants so if you have either of these you really have to be vigilant about finding and treating the problem.
The symptoms are very easy to spot. Firstly you might notice that branches or your entire plant if you’re particularly unlucky to have been defoliated. This is the only insect that will cause severe deflation on this plant. If you look closely you might notice the black head, and creamy white body that looks like a caterpillar but has yellow-orange splotches and black spots. If you’ve caught one of these on your leaves, you have caught them red-handed. The adults become shiny insects, black, with greyish-black wings that can reach up to 8 millimetres in length.
You can physically check your plants between April and October and remove them by hand if possible or replace your Barberry plant with something else that this pest doesn’t eat. More effective though is using a pesticide control measure. You might have an infestation that is simply too much to pick away by hand in which case you can spray a pesticide at dusk for the most successful results. Organic insecticides can be very useful but you might have to use several applications to get control of the issue.
The main thing to do is check regularly and spray the larvae before they can have time to stip the leaves but you have to act quickly.
Last update on 2020-09-19 at 15:42 / Affiliate links / Images from Amazon Product Advertising API