Anthracnose

Anthracnose is a widespread fungal disease that affects many different types of fruit bearing plants and trees as well as grasses. For each case of anthracnose, the specific type or family of fungus could be different. For anthracnose of grape and dogwood, it is the family of fungus called Elsinoe. For Ash, Oak and Sycamore trees, the fungus that causes anthracnose belongs to the family called Apiognomonia.

Colletotrichum is a family of fungus that causes anthracnose of peppers, strawberries, tomatoes, cucurbits, and corn. Bluegrass and bentgrass, which are grass species commonly grown on golf courses and putting greens, are also affected by this fungus.

Although the family of fungus differs for individual cases of anthracnose, there is a commonly accepted list of symptoms, and effects of the disease.
 
Anthracnose affecting the fruit of a tomato plant.
 
Anthracnose of tomato
Photo courtesy of cropsci.illinois.edu

Athracnose on the fruit of the pepper plant.
 
Anthracnose of pepper
Photo courtesy of ohioline.osu.edu 

General Anthracnose Symptoms (Fruit Bearing Plants)
  • Lesions can grow and multiply on the fruit
  • Disease attacks fruit development of the plant
  • Spores of the fungus spread rapidly in a garden
  • Disease eventually causes the fruit to become rotten
  • Black structures or small black dots called acervuli form on the fruit
  • Circular or angular sunken lesions develop on immature fruit (can be any size)
  • Steams and leaves can be affected with irregular brown spots and dark brown edges

Anthracnose on the leaves of a silver maple tree.

Anthracnose on silver maple tree, foliar portion

Photo courtesy of urbanext.illinois.edu


Anthracnose on the twig portion of a sycamore tree.

Anthracnose of sycamore tree

Photo courtesy of urbanext.illinois.edu

Symptoms Affecting Trees
  • Leaf lesions can also form
  • Invades twig, bark and foliar portions of the tree
  • Causes blight of the shoots, leaves and twig portions
  • Stem symptoms include dieback on twigs and cankering
  • Leaf symptoms include irregular brown blotches on foliar portions
  • Depending on the species and conditions, infection can be mild to severe
  • Disease can cause defoliation and troublesome cankers which weaken the tree
Videos for Identification of Anthracnose on Plants

The fungal spores of anthracnose are winter hardy, and can overwinter in almost any plant debris. They are able to survive year-round in many conditions, and when the warmth of spring and summer comes, they begin to multiply again. They can come from numerous sources, but can also exist in the soil already, which is the case most times. The fungal spores of anthracnose spread across large areas via the wind or rain.

In general, anthracnose fungal spores will begin to grow on plants early, before any fruit production takes place. As the growing season becomes warmer and the plants develop, the fungus starts to affect the foliar and fruit portions of the plant.


Conditions that are most favorable for the growth of anthracnose fungal spores are mildly warm and wet areas, and medium to high humidity conditions. As an exception, anthracnose of dogwood is special in that the fungus can grow in cooler, more elevated conditions.

Dogwood anthracnose has been especially decimating in the United States. The particular fungus that causes it, Discula destructive, entered areas near Connecticut and Washington State at the same time in the middle of the 1970s. This particular case of dogwood anthracnose is centralized to the United States, and has not been prominently discovered outside of the U.S. on any other species of dogwood.
 
Athracnose on flowering dogwood tree.
 
Anthracnose of Flowering Dogwood (Cornus florida)
Photo courtesy of plantclinic.cornell.edu

Prevention & Control of Anthracnose

Gardeners can take many steps to prevent or control the spread or potential infection of anthracnose in their plants. For edible crops like peppers and tomatoes, try to segment the plantings, as both plants are susceptible to the same family of anthracnose fungus, Colletotrichum. If signs of anthracnose show up, rotate the crop out of the affected area. Crops should be rotated out of infected areas for at least 2 or 3 years. Also, ensure that the soil is well drained. Excess soil moisture can harbor anthracnose fungal spores and provide a growing medium for them.
 
For trees, keep up an effective pruning strategy to limit possible anthracnose outbreaks and lessen the amount of potential spores on the tree itself. Make sure to keep dead plant debris clean from the ground around the trees. Rake and discard or compost leaves from these areas in the fall.
 
Anthracnose is a disease that will never be completely eradicated from an area. It can also recur several times throughout the growing season depending on weather and soil conditions. As part of a complete care program, a regimen of fertilizer application and fungicide use can optimally prevent and control anthracnose fungal spores from taking over plants.
 
We offer a natural gardening product called VermActant, which will help prevent anthracnose in the following ways:
  • Enhances the efficiency of fertilizer
  • Improves the availability of nutrients in the soil
  • Improves soil structure, and water-holding capacity
  • Encourages "good-guy" fungi to protect plant roots from invading pathogens like anthracnose
  • Promotes a healthy soil ecosystem as well as stimulating the growth, flowering and fruit production of plants
In combination with this, our product Emerald Mist provides exceptional fungicidal protection against a large variety of foliar and soil-borne fungi.
 
How Emerald Mist can help fight against anthracnose:
  • Provides outstanding foliar and soil nutrition
  • Enhances the growth of plants with earth-friendly micronutrients
  • Great for protection against a variety of foliar and soil based fungi
  • An environmentally friendly way to control and prevent a disease like anthracnose at the root level

To view a brief, field identification video about anthracnose, click here.

For additional information on our natural gardening products that promote a healthy and vigorous garden, contact us.