Garden Q&A: What causes holes in lupin leaves, and what's the remedy?

Irish Examiner

03-06-2025

Question
My lupin leaves are full of holes, and the plant doesn't look great. What's causing this, and how can I fix it?
Answer
If your lupin leaves are full of holes at this time of year, it's usually down to slugs or an aphid, such as the lupin aphid — and quite often a combination of both.
Slugs tend to feed at night, leaving irregular holes and sometimes a silvery trail behind them, especially in damp conditions. At the same time, lupins are often targeted by a specific aphid, large, pale green to grey in colour, that clusters on the stems and undersides of leaves.
Lupinus, commonly known as lupins. File picture
While aphids don't eat holes directly, they weaken the plant and open the door to fungal infections and distortion, which can cause further leaf damage.
The best approach is to remove any visible pests by hand and spray the affected parts with a hose or some soapy water. Encouraging ladybirds also helps.
A well-fed, healthy lupin in full sun will always stand a better chance of fighting off pests naturally.
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