Having an apple tree in your yard can be a lot of fun. Not only do you get to enjoy beautiful blossoms every spring, but come fall, you'll have apples to enjoy. That is – if you can keep your tree free of diseases like apple scab. Here's what you need to know about this common fungal disease, how to treat it, and how to prevent it.
What causes apple scab?
Apple scab is a fungal disease caused by a species called Vernturia inaequalis. A tree becomes infected after the spores of the fungus land on the tree, germinate, and then form lesions on the tree's fruit or leaves.
What are the signs of apple scab?
The first sign of apple scab is the formation of black or brown, scabby-looking lesions on the apple tree's leaves or twigs. As the season progresses, these lesions become larger and may appear on larger branches. Once the fruit sets, you'll notice scabs on it as well. Sometimes, apples only develop small scabs about the size of a pencil eraser. When this is the case, the fruit is generally still edible, though you'll want to cut around the scabbed area. Other times, the scabs will be larger and cover a greater portion of the fruit, rendering it mostly inedible.
What should you do if you think your tree has apple scab?
If you're noticing symptoms of apple scab on your tree, it's too late to save the apples from that season from developing scabs. But there are things you can do to prevent the tree from becoming re-infected the next spring. When the fruit begins to fall, make sure it's cleaned up promptly. Otherwise, the fungal spores will over-winter on the ground and re-infect the tree in the spring. Also clean up fallen leaves promptly in the autumn. Have your tree pruned in the late winter to remove any damaged and dying branches, as these are more susceptible to infection.
Also, make arrangements for a tree service company like All Around Landscape & Tree Service to come spray your tree with fungicides. This should be done once as soon as the buds appear, and then every few weeks until it's time to harvest the apples. Your tree service expert can recommend a specific spraying interval based on your climate, the amount of rain your area receives, and the severity of the apple scab infection your tree dealt with in the past year.
Apple scab is not usually deadly, but it can ruin your apple crop. Keep an eye out for signs of this infection, and take action to prevent re-infection if you do notice symptoms.