Over winter, a fungus known as Colletotrichum gloeosporioides spends time in dead leaves and twigs. During the spring, rainwater splashes and spreads the spores for them to germinate, entering live tree growth. Due to how easily these spores spread, this disease can seemingly appear out of nowhere. Learning how to identify, treat, and prevent anthracnose is critical to keeping your trees healthy.
Brown, small, sunken spots can appear on fruits and vegetables and affect any part of said plant. Moist weather will cause groups of pinkish spores to form in the center of dark spots, causing the vegetation to eventually rot.
Anthracnose will generally begin as small brown or yellow spots with irregular edges, growing larger over time. If left unchecked, the spots will continue to grow until the entire leaf is covered and eventually dies. Similarly, it can attack the tips of new twigs, killing young blossoms and leaves—completely defoliating the tree.
The best way to get rid of anthracnose and stop it from spreading to other plants is to remove infected wood, leaves, fruits, and vegetables. Because spores can spread easily through wind and water, you’ll want to either seal them in a bag far away from your garden or burn them entirely. Do not put them in your compost, as they will infect everything else.
You can also use a copper-based fungicide to help manage the disease. While it won’t save an already infected leaf, it can kill off spores that would have spread to other parts of the tree. However, spray this fungicide sparingly, as high levels of copper can kill off important insects and microbes critical to your tree’s health.
Trees have to be trimmed during particular seasons, and if your tree is experiencing anthracnose in the early spring, your tree may need some late fall or early winter pruning. In doing so, you remove the home and food source the fungi dwell in, so they can’t spread to other live parts of the tree during spring. Additionally, ensuring fruits and vegetables don’t touch the ground and practicing good soil irrigation techniques can help prevent anthracnose altogether.
Learning how to identify, treat, and prevent anthracnose is relatively easy once you have the right knowledge. Be sure to regularly check your trees, stick to best gardening practices, and properly dispose of diseased plants.