How To Treat Apple Tree Rust

Apple tree rust can be damaging to the health and integrity of your apple trees. To restore your trees to their former glory, learning how to treat apple tree rust is essential. Here we’ve outlined a few key steps to follow in order to successfully treat apple tree rust.

First of all, you’ll want to identify which rust pathogen is affecting your apple tree. These can usually be identified by examining the apple tree leaves and spots on the fruit. Knowing the exact rust species is a critical step for successful treatment.

Once you know the rust species, you’ll need to select an appropriate treatment and begin applying it. Most treatments involve fungicides, often mixed with other ingredients to maximize their effectiveness in treating rust. Be sure to follow the instructions on the fungicide label exactly, as incorrect or careless application may cause more damage than good.

You should also keep an eye on the weather forecast and wait for suitable weather conditions before applying the fungicide. Preferably wait until the temperature is 65°F or above and there is no rain in the forecast. Humidity also affects the effectiveness of fungicides and a dry day will allow for optimal results.

Follow up application is also very important. Fungicides usually need to be applied several times to ensure the rust is eradicated. Repeat the treatment a week or two after the initial application, always ensuring that the weather conditions are favorable.

Finally, prune the infected branches once the rust has been treated. This will help prevent the disease from reoccurring and reinfecting the tree. Make sure to disinfect your pruning tools after use, to prevent any spread of the disease.

Treatment Options

Depending on the rust species, there are a variety of treatment options available. Perhaps the most common forms of treatment involve fungicides, specifically those containing propiconazole or chlorothalonil. These compounds are widely used to treat rust species, especially those found on apple trees. Alternately, biological control can also be used as a rust treatment, where inoculants such as Trichoderma spp. and Phanerochaete chrysosporium are conveniently added to the soil.

Foliar spray treatment is also becoming increasingly popular. Here a fungicide solution is sprayed onto the tree using a specialized sprayer. Systemic treatment options can also yield good results in the case of apple tree rust. Here fungicides are administered to the trunk of the apple tree and the solution is absorbed via the plant’s vascular system.

Finally, copper based fungicides can also be used for treating rust species. This is most helpful for treating red cedar rust, but can also be used for other rust species as well. As with systemic treatment, copper based fungicides should also be administered to the trunk of the tree.

Prevention Strategies

In addition to treating apple tree rust, you’ll want to consider the various prevention strategies available. The most logical step to take is to purchase and plant rust resistant apple tree varieties. This can significantly reduce the chances of rust occurring, but even resistant varieties cannot be completely immune to the disease.

Taking care of the tree is another important preventive measure. Ensure that your apple tree has all the necessary nutrients, as well as proper soil drainage conditions. In addition, avoid overcrowding the tree by pruning it regularly. Lastly, make sure to clean up fallen leaves and fruit to further prevent rust from occurring.

Another proven preventive measure is to make use of fertilizers that contain nutrients and minerals known to inhibit rust. This can have the added benefit of promoting growth and boosting overall tree health. These fertilizers are often available from your local garden center.

Finally, use of fungicides can also be employed as a preventive measure. Regular and careful application of fungicides such as propiconazole and chlorothalonil can help reduce the chances of rust developing on your apple tree.

Further Treatments

If you already have an outbreak of rust on your apple tree, there are additional treatment measures which can be used. For example, another common approach is to scrape off the affected fruit and leaves and destroy them. This prevents the egg masses from hatching and further spreading the disease.

Alternatively, copper sulphate can be applied to the fungicide and left to soak for several hours in order to render the eggs sterile. This can help prevent the spores from further developing, thus reducing the chances of rust occurring again.

Lastly, it’s possible to spray the tree with a neem oil solution. Applied as a foliar spray, neem oil has been known to help control the development of rust spores. It also works great as a natural and biodegradable preventive measure, too.

Clean Up And Sanitize

Regardless of which treatment method you decide to employ, it’s essential to clean up the infected apple tree thoroughly afterwards. This includes pruning out any dead or dying branches, as well as removing all fallen leaves and fruit from the area. Failure to do so can result in a quick re-infestation of rust, as the spores can re-enter the tree easily through wind or water.

Sanitizing your pruning and gardening tools can help, too. Sometimes spores can remain on the blades which can then be transferred to another tree when pruning. Therefore it’s always important to thoroughly sanitize your tools after applying the rust treatment.

At the same time, consider using a protective spray to help reduce the chances of new spores from entering your tree. These sprays typically contain components such as potassium bicarbonate or sodium bicarbonate, and form a barrier against new rust spores.

Keeping the area around your tree clean and free of rust spores is also a great way to prevent the disease. This includes any nearby wild trees, weeds or grasses which may be carrying rust spores.


By following the steps outlined here, you should be able to successfully treat any apple tree rust. In addition, making use of preventive measures can help reduce the chances of rust developing in the first place. Lastly, remember to clean up the infected tree and sanitize your tools after applying the treatment.

Gordon Wesson is an environmentalist and author who lives in the Pacific Northwest. He has been writing for many years about topics related to trees, the environment, and sustainability. In particular, he is passionate about educating people on the importance of living in harmony with the environment and preserving natural spaces. He often speaks at conferences and events around the country to share his knowledge with others. His dedication to protecting our planet makes him one of the leading voices in his field today.

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