Teeny tiny mites have caused this damage to the tips of new branches on Hawthorn bushes (Crataegus species). Mites are so tiny that they can feed on individual plant cells, and it is this feeding that distorts and deforms the new leaf growth. These particular mites are called Dasineura crataegi, and the galls they create are known as Hawthorn button-top galls.

Apparently, these galls are quite common but I’ve only seen them recently. All plant growth in the field where these Hawthorn bushes are growing is usually cut to the ground in late Autumn but that cut wasn’t down last year, possibly because it was too wet. This has allowed Hawthorn seedlings to grow where they usually wouldn’t, and it is on these young Hawthorns that the mites are thriving. It will be interesting to see if the galls appear again next year if the annual cut goes ahead.