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How to Identify, Control, and Treat Anthracnose

Fungal anthracnose attacks these young grapevine leaves.

Photo Credit
Photo by CSIRO ScienceImage via Wikimedia Commons
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Prevent This Fungal Disease in Your Garden

Catherine Boeckmann
Pest Type
Plant Diseases

Anthracnose is a fungal disease that 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.

What is Anthracnose? 

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.

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Identification

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-identification-disease.jpg
Anthracnose can affect many plants with its brown spots, including this cucumber leaf.
Photo Credit: Rutgers University. 
Gardening Products
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.
Plant Disease
About The Author

Catherine Boeckmann

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

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Comments

I'm a Master Gardener in NC...this is what we recommend for organic controls...

2. Entrust®. The active ingredient in Entrust® is spinosad, which is made from spinosyn, a substance produced from the fermentation of a soil-dwelling bacterium. Entrust is very expensive but it only takes a tiny bit. For example, only 0.159 ounces of the pesticide is needed per gallon of water for a mound drench to treat fire ants. Each mound will require 1-2 gallons of the mixture depending on its size. Best results will be achieved if applied after a recent rainfall and when temperatures are between 65-85°F. Due to its high price, this product must be mail-ordered. Entrust® is used by organic growers for control of a number of vegetable pests. A one pound bag of Entrust® can retail for over $500, but this provides way more product than a single grower can use during one growing season which is why growers sometimes go in together to purchase a bag. Contains 80% active ingredient by weight.Suppliers include Johnny’s Selected Seeds and Peaceful Valley Farm Supply.View the Entrust® label.
3. Monterey Garden Insect Spray. This is another OMRI-approved spinosad product but it isonly labeled for home garden use. It is not for use on farms. This product is a liquid concentrate with 0.5% active ingredient.Suppliers include Biocontrol Network, Monterey, and Planet Natural.View the Monterey Garden Insect Spray label.4. Greenlight Fire Ant Control with Conserve. OMRI-approved spinosad product but it isonly labeled for home garden use. It is not for use on farms.
BaitsBaits are granular products that are collected as food by foraging ants. The bait granules (generally corn grit) are impregnated with oil to make them attractive to the ants as food. The ants take the bait back to the mound and feed it to the queen and the rest of the colony. According to North Carolina State University entomologist Dr. Hertl, the use of baits can reduce environmental contamination from insecticides since baits contain a very small amount of insecticide.Spinosad is the active ingredient in the organically approved baits.The best time to apply baits is in the early evening. Do not apply baits when the ground is wet as moisture can cause the oils in the bait to become rancid.Most bait products describe two options for applying the product: 1) broadcast application over a large area and 2) mound application of the bait over the mound and extending to about two feet from the mound.Mound applications are recommended because they will have the least impact on foraging native ants which directly compete with the imported fire ants. If bait is broadcast over a large area, it is likely to be ingested by foraging native ants and other insects.

Fire ant taking a bait granule back to the nest.

There are at least two organically approved spinosad baits:

1. Ferti-lome® Come and Get It! Fire Ant Killer. This product can be used on lawns and gardens, nurseries, pastures, and fruit & vegetable crops. See label for complete list of labeled use sites. Contains 0.015% active ingredient by weight.View the Ferti-lome® Come and Get It! Fire Ant Killer label. This on-line label does not have the OMRI label on it but this product is OMRI-approved and the actual bottles on the shelves now do have the OMRI label.
2. Greenlight Fire Ant Control with Conserve®. This product is labeled for use on lawns, around ornamental plants, and in home gardens (one acre or less). Contains 0.015% active ingredient by weight.These baits are available at both Pittsboro Feed and Country Farm and Home Supply in Pittsboro. Check your local farm and garden stores for supplies near you.

Kathryn Evans (not verified)

13 years 4 months ago

Spray plants with milk and water mixture, this works wonders!