Rusts appear as orange, yellow or sometimes white pustules on the underside of the leaves. It can often occur in mild, moist conditions. Many rusts affect both ornamental and productive plants. Rusts are often specific to types of plants, and one rust species may not affect another plant of a different species. Rust infestations are common on fuchsias, roses, calendulas, geraniums (especially zonal forms), hollyhocks, frangipani as well as raspberry and blackberry. Spores are spread by wind and moisture from infected plants to healthy plants.
Prevention is the best form of control, so check plants for any symptoms of disease. Once it appears, prune and remove infested parts (such as leaves) or affected plants. Remember to sterilise pruning tools and secateurs with beach between plants, to help stop the disease from spreading. Also, if you are in an area where rust is prevalent, grow rust-resistant varieties of plants if they are available.
Rust outbreaks on ornamental plants may be treated with a fungicide spray such as EarthCare Rose Black Spot & insect spray. When spraying the foliage follow the directions on the back of the pack and spray both sides of the foliage. Repeat application maybe needed for further control. Remember not to spray when beneficial insects and bees are around.
A healthy garden can also help prevent disease infestation. If your plants are strong and healthy, they may be able to handle and reduce the stress of pests and diseases. Applying Seasol regularly every two weeks during the year can help them to cope with environmental stress. Keeping plants fed with fertilisers such as PowerFeed All Purpose including Natives, better watering and appropriate light exposure can also help build tougher plants.