Rust
Rust enjoys warm and damp conditions and can totally destroy a rose if infestation is bad enough.
Symptoms first appear in early summer in the form of small bright orange pustules on the undersides of leaves. They often go unnoticed until the disease spreads. They become larger, changing colour to brown and then to black. In a bad attack the spores will kill the leaves and eventually spread to the stems, which will start to die back. Control is almost impossible at this stage when the only real option is to dig up the plant and burn it. If caught early enough however, pick off and burn the infected leaves and keep an eye out for reinfection. As in the case of black spot, rust spores will lay dormant on dead leaves or in the soil during the winter, so gather up any fallen leaves and wash the plant and surrounding soil with a fungicide whilst it is dormant. The following season ensure that a spraying regime is started early and repeated regularly.
