Anthracnose: How to Identify, Control, and Prevent Anthracnose | The Old Farmer's Almanac



Fungal anthracnose attacks these young grapevine leaves.

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Photo by CSIRO ScienceImage via Wikimedia Commons
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How to Identify, Control, and Treat Anthracnose

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What is anthracnose? This fungal disease affects many plants, including vegetables, fruits, and trees. It causes dark, sunken lesions on leaves, stems, flowers, and fruits. It also attacks developing shoots and expanding leaves. It can spread very quickly during rainy seasons. Learn how to treat plants affected by anthracnose and how to prevent it.

Anthracnose is a general term for a variety of diseases that affect plants in similar ways. Anthracnose is especially known for the damage that it can cause to trees. Anthracnose is caused by a fungus, and among vegetables, it attacks cucurbits.

Anthracnose can survive on infected plant debris and is very easily spread. Like rust, it thrives under moist and warm conditions and is often spread by watering.


How to Identify Anthracnose

  • On leaves, anthracnose generally appears first as small, irregular yellow or brown spots. These spots darken as they age and may also expand, covering the leaves.
  • On vegetables, it can affect any part of the plant.
  • On fruits, it produces small, dark, sunken spots, which may spread. In moist weather, pinkish spore masses form in the center of these spots. Eventually, the fruits will rot.
  • On trees, it can kill the tips of young twigs. It also attacks the young leaves, which develop brown spots and patches. It can also cause defoliation of the tree.
Anthracnose can affect many plants with its brown spots, including this cucumber leaf.
Photo Credit: Rutgers University. 
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Control and Prevention

How to Control Anthracnose

  • Remove and destroy any infected plants in your garden. For trees, prune out the dead wood and destroy the infected leaves.
  • You can try spraying your plants with a copper-based fungicide, though be careful because copper can build up to toxic levels in the soil for earthworms and microbes. For trees, try a dormant spray of bordeaux mix.

Prevent Anthracnose

  • Plant resistant plants, or buy healthy transplants.
  • Plant your plants in well-drained soil. You can also enrich the soil with compost to help plants resist diseases.
  • Water your plants with a drip sprinkler, as opposed to an overhead sprinkler. Don’t touch the plants when they are wet.
  • Keep ripening fruits from touching the soil.
  • Remember to rotate your plants every 2 to 3 years.
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann

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