Making Smarter Landscaping Choices

Apple Scab: How To Spot It, And What To Do About It

Apple scab is a highly destructive fungal infection that can render an entire apple crop inedible if you do not spot and treat it promptly. If you have one or more apple trees on your property, it's important that you watch out for signs of this condition, and act quickly if you suspect an infection.

Signs of Apple Scab

Usually, the first signs of an apple scab infection appear in the early spring around the time the tree blooms. If you look at the underside of the blossoms, you may spot dark brown or olive green spots. As the season wears on, you'll notice these spots begin spreading outward to the tree's smaller twigs. The spots start off fuzzy – the fuzziness is caused by the fungal spores  -- and then they become dry and cracked as the spores are released.

When the fruit appears on the tree, apple scab causes dark brown lesions to appear on their surface. These lesions are often perfectly round. As the fruit ripens, the lesions take on a scab-like texture – hence, the disease's name. Mild infections may leave the fruit in edible condition ; the apples may just have one or two inedible spots on their skin. More severe infections, however, will yield the apples basically inedible. Thus, it's essential to treat the disease as soon as it is spotted.

Treating Apple Scab

Typically, trees on large farms are sprayed with fungicide as a preventative measure against apple scab. However, if you just have an apple tree or two on your property, you may not take this step. But when apple scab is spotted, you should immediately have your tree sprayed with a fungicide designed specifically for fruit trees. Your tree service specialist will then recommend having your tree re-sprayed periodically to continue combating the infection.

If there are any large lesions on the tree, an experienced tree care specialist can trim them out to prevent the spread of the fungus. Badly damaged branches may be pruned away. If the fruit is already beyond saving, removing it from the tree will help reduce the spread of the infection. Treating the infection aggressively the first year will hopefully mean you have a healthy, disease-free apple crop the next year.

It is easier to prevent apple scab than it is to treat it. Thus, if you're planting new apple trees, it's wise to choose a resistant variety, like Ida Red or Golden Delicious. Visit a tree care company like Ironwood Earthcare for more information.