Raspberry Rust, sometimes known as raspberry yellow rust affects the foliage of raspberry canes. Attacks are worst during prolonged wet weather. In early summer small yellow raised pustules can be seen on the upper surface of the leaves, usually affecting the lower leaves. Later in the summer these pustules become less conspicuous, but a high number of small orange pustules appear on the lower leaf surface, often with small yellow spots which correspond to those pustules on the upper surface. Scores of these 'summer spore' pustules will be present on a single leaf. Severe infestations may result in premature shedding of leaves. During late summer these orange pustules are gradually replaced by black ones which contain overwintering spores.
Product Solution: Spray with Fruit and Vegetable Disease Control which may give incidental control.