All About AnthracnoseA disease that attacks trees, shrubs, and smaller plants, anthracnose is caused by a number of different fungi from the Colletotrichumgenus. It is notable for the following characteristics:
Weather Specificity- Anthracnose needs wet, cool conditions in order to spread. It is most successful when the temperature is between 75 and 85 degrees Fahrenheit and the environment is relatively moist. In Southeast Michigan, these conditions are most likely to abound during the spring, meaning you should look out for signs of the disease during this time.
Leaf Damage- When a tree or other large plant becomes infected with anthracnose disease, its leaves tend to develop yellowish or brownish lesions. Over time, these lesions will grow darker and larger and may come to span entire leaves. If this problem persists long enough, it can cause leaves to fall off in large quantities. In addition to lesions, anthracnose causes small brown and tan dots to develop underneath the leaves; this makes the disease easy to distinguish from other fungal infections.
Other Harm- Besides leaves, anthracnose disease attacks the stems of trees, and if the trees produce fruit, it will affect that as well. Fruit that has been infected will develop sunken, dark spots, which grow larger over time; clusters of pink spores will eventually develop in the center of these spots. As with leaves, a prolonged infection can cause fruit to rot away and fall off.
Anthracnose disease tends to spread quickly from tree to tree. Rain, wind, insects, and even garden tools can carry the spores around your yard; it is especially common for homeowners to distribute them when they water their trees. The fact that it spreads so easily and quickly underscores the importance of getting an anthracnose infestation under control as soon as it breaks out.
Anthracnose TreatmentWhen it comes to anthracnose, preventing infection is significantly easier and more effective than curing it. Many trees come in varieties that are resistant to the disease; all things being equal, you should opt for these for all your trees and other plants. You should also make sure the soil you’re using has been fully drained and that has all the nutrition the plants need to grow strong. These steps will make it harder for spores to reach the trees while giving them the strength to shake off any fungus they do come into contact with.
Another strategy for preventing anthracnose is to rely on drip irrigation instead of traditional sprinklers when watering your trees. This gives them enough water to grow strong without creating the moist conditions that foster fungal growth. In addition, you should prevent any ripening fruits on your trees from coming into contact with the soil. Finally, if you rotate your plants as often as possible, you make it harder for anthracnose to mount a successful attack.
Even with all these steps, there’s no foolproof way to stop anthracnose from infesting your trees. When this happens, the following steps will limit the spread of the disease and help you quickly restore your yard to full health:
Eliminate Infested Material- Remove any plants or plant materials that have been severely infested, take them to an isolated location where spores cannot spread, and destroy them. For trees, you don’t necessarily have to get rid of the entire plant, but you must remove any leaves, fruits, or branches that have been infected, as well as any dead sections of the wood.
Select a Fungicide- There are a number of different fungicides that can kill anthracnose. These include neem oil, sulfur powders, copper sprays, and other biological and chemical options. Choose the one that is best suited to the severity of the infection and the environmental needs of your yard.
Apply Repeatedly- It’s often necessary to apply the fungicide several times, often once a week until the infection has been eliminated. Make sure not to spread too much of it or apply it too often, as many fungicides can kill earthworms and other organisms that are essential to the natural environment.