Big bud disease of blackcurrants

This is a good time of year to check over your Blackcurrant bushes for signs of the mites that carry a mycoplasma disease which causes reversion. Reversion disease seriously reduces yields of fruit. In early summer when the mites emerge from the buds they can be carried on the wind to new plants.

Examine the buds carefully and look for buds that are swollen and rounded. The buds should be narrow, elongated and pointed...if they're sharply pointed the buds are healthy. Infected buds produce distorted leaves in Spring or no leaves at all because the mites live in the buds and suck the sap of the embryonic leaves.

If the infestation is really light you could try removing all the affected buds (don't drop them on the ground) take them home(off the site) and burn them. If they are still present next year you will need to remove the plants and again preferably burn them off site. However, Big Bud is very infectious and not dealing with the problem will mean that everyone on site could have their blackcurrants infected in a very short time so you won't win any prizes in the popularity stakes.

There are no pesticides available to the home gardener to deal with the mites, but if you have had a problem and wish to replant the Cultivar 'Ben Hope' is supposed to be resistant. There have been incidences of Big Bud on our site in the very recent past so don't be complacent.

If you are unsure whether you have big bud or not I am happy to check your bushes for you, just contact me via treasurer@hraa.org.uk.

Jude Ongeri

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