How To Treat Powdery Mildew On Avocado Tree

Avocado trees are popular plants, prized for their delicious fruit, abundance of foliage, and hardy nature. But even hearty avocado trees can be vulnerable to disease like powdery mildew. This fungus is especially troubling damage as it affects the plant’s growth and can reverse gains you have seen in the vibrancy and yield of the fruit. Fortunately, powdery mildew is easy to recognize and treat.

Recognizing Powdery Mildew

It is important to identify powdery mildew as soon as possible in order to properly address the problem. To do this, you’ll need to observe the avocado tree carefully. Powdery mildew is easily recognizable because of its powdery, white coating on the leaves of the plant. Each spot will contain its own series of small, white circles. It is most active in the sunny hours from late spring to early summer.

Removing Infected Limbs

Once you are sure your avocado tree has powdery mildew, you should take measures to remove any areas which are badly infected. These parts may provide ideal conditions for the fungus to spread. When cutting off the infected parts of the plant, use sterile clippers or pruners so you are not touching the plant with contaminated tools. Cut several inches below the mark of infection, as well as some of the healthier-looking parts of the plant, to ensure the disease will not spread further.

Preventative Measures

Once your avocado tree is clear of fungus, it is essential to take daily preventive measures to keep it that way. Keeping the area and soil clear of debris, fallen leaves, and other items will reduce the risk of infection significantly. Additionally, attention to water and fertilizer schedules should be taken as too much or too little of either will also open the potential for fungus to appear. If possible, spraying a preventative fungicide periodically will also reduce the chances of powdery mildew appearing again.


If your avocado tree is already infected, there are a few kinds of fungicides which can help to clear the infection. After removing the infected limbs and foliage, fungicides can be sprayed onto the remaining areas and leaves. As prevention is better than cure, applying fungicides before any signs of fungus appear should be done at least every couple of weeks.

Cultural Practices

Healthy cultural practices are essential to keeping powdery mildew away from your avocado tree. Although avocado trees are generally drought tolerant and can survive in most climates, warm temperatures combined with relative humidity greater than sixty percent can encourage fungal growth. Ensure the soil around the tree is getting enough air and keep it well-drained as soggy, sodden soil also promotes the growth of fungus. Lastly, avoid over-pruning or over-fertilizing your avocado tree as too much can also create conducive conditions for fungal activity.

Closing Thoughts

Treating and preventing powdery mildew on avocado trees can be a challenge but with vigilance, patience and a solid understanding of the disease and its treatments, you can keep your tree safe from further infection and keep it healthy. Make sure to stay connected to a local agricultural expert who is familiar with avocado diseases in your area and can provide additional insight and advice.

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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