The canes (stems) of the bushes infected with Cane Spot have clearly defined dark marks on them with a purple border. These normally first appear on the lower parts of the canes, and gradually work their way upwards. The marks tend to be in the shape of a 'squashed' circle (elliptical) and are rarely larger than 1cm (1/4 in) long.

Unless Cane Spot affects large parts of the canes (and other parts of the bush) they are probably best ignored. Regular clearing of debris at the base of the plant will prevent it's spread. In addition, ensure that all canes which have produced fruit are removed as soon as possible.

If the disease does take hold, the young shoots will shrivel. In these cases, the treatment is to spray with a copper fungicide and cut out the worst affected canes.

Cane Spot is a fungus which over-winters on the canes, springing back into life late Spring to early summer.