These are my latest gall finds, caused by the mite species Phytoptus avellanae, shown here on Hazel (Corylus avellana) though they can also affect the buds of Filbert (Corylus maxima). The feeding of the mites on the plant cells within the buds causes those buds to swell and multiply. You can see a comparison in my photo below, the mite-infected gall bud on the left, the normal bud on the right.

The mites that cause these galls are tiny, so rarely seen, but the Dutch Bladmineerders website has some excellent photos showing them in minute detail. As with so many galls, they are thought to be widespread in Britain but are not well recorded. So, if you’re out and about enjoying a spring walk and spot some Hazel, do please cast an eye over the buds, and record any galls you see. Citizen scientists really do make a difference to our knowledge of the natural world around us.