What is Anthracnose?

Anthracnose is a disease in plants caused by infection with fungi. Depending on the plant and the fungal species involved, a variety of symptoms can appear, including damage to the flowers, leaves, and branches. People sometimes refer to anthracnose infection as “blight” because the infected plants tend to look blighted and stunted. There are a variety of techniques which can be used to control and prevent anthracnose in plants, trees, and shrubs.

As a general rule, this infection occurs in warm, humid climates, usually during the spring, when the plant is developing. The fungus attacks the growing buds and shoots of the trees, causing them to start to brown or blacken. If the plant is small or not very hardy, it may begin to wither and droop as the damage spreads. An especially virulent version, dogwood anthracnose, can occur in cooler climates as well.

Fungi in a number of genera including Stegophora, Colletotrochium, Gloeosporium, Discula, and Apiognomonia can cause anthracnose infections. The infection is host-specific, which means that the appearance of the disease on one plant or tree in the garden does not necessarily mean that it will spread to other garden plants. The fungi typically incubate in the soil, taking advantage of changing environmental conditions or the appearance of new plants to start growing.

One of the best ways to prevent infection is to take good care of plants and trees. By ensuring that their plants are well-watered and well-fed, gardeners can keep them hardy and healthy so that they will resist fungal infection. It also helps to keep branches trimmed to promote the circulation of light and air, as the fungus needs moist conditions to thrive. Fungicides can be applied in the spring to prevent the growth of the fungus, but this is only recommended in areas with a history of anthracnose infections.

If a plant does become infected, the damaged parts of the plant should be pruned away and destroyed. It is also advisable to rake up and destroy fallen leaves and flowers. In the event that a plant becomes severely blighted, it may be more practical to remove it and plant a more resistant species. Gardeners should also be aware that fungal spores can spread in the air, which means that if signs of infection occur in the neighborhood, they can spread. Therefore, it is in everyone's best interests to address infection as early as possible.