Blackcurrant Big Bud Mite
The signs are more easily seen in late winter, when infested buds have become abnormally swollen and rounded (healthy buds are pointed).
Other symptoms are: Dried up buds, lack of leaves in spring, stunted foliage and few flowers.
An infested bud can contain hundreds of breeding mites that feed by sucking sap from the embryonic leaves within the bud.
Reproduction takes place most of the year round, but less during the winter months than at any other time.
The tiny mites, that are scarcely perceptible to the naked eye (less than 1mm in length) emerge in early summer, and spread over the plant/s in search of new buds to infest.
They live almost entirely inside the buds of the Black Currant, but now and then attack the Red and the White varieties.
As the buds die the mites migrate to other buds, they do this by either crawling and jumping on to the outside of the bud and sticking to it by means of a sucker on their tail.
They can also migrate by sticking to birds and bees where they are brushed off on to other shrubs.
Migrations are frequent, but most numerous from April to June.
Currently there are no pesticides available to the amateur gardener.
A laborious cure for lightly infected plants is to manually remove affected buds during the growing season then again in winter when the problem is most noticeable.
If the problem is severe dispose of the plants and replace them.
There are some resistant cultivars on the market so check with your supplier before making a purchase.