Why Are My Leaves Falling from My Crabapple Tree?

Apple scab, caused by the fungus Venturia inaequalis, is a widespread problem for homeowners with crabapple trees in Otisville, Michigan. This disease thrives in cool, wet spring conditions, which foster the growth of the fungus.

What Is Apple Scab Disease

On crabapple trees, apple scab initially appears as dark, olive-green spots on the upper side of the leaves. As the disease progresses, these spots turn brown or black, causing the leaves to curl, distort, or drop early. In severe cases, apple scab can lead to extensive defoliation, weakening the tree and reducing its overall aesthetic value, and in extreme cases, may even cause the tree to die over time.

Typical Symptoms of Apple Scab Disease:

• Dark fungal lesions on leaves
• Reduced blooming and fewer flowers
• Early leaf drop in mid-summer
• Defoliation occurring earlier than usual
• Increased vulnerability to pests and secondary diseases due to stress
• Gradual branch dieback and tree decline

To control apple scab, fungicide treatments should be started early in the spring before the fungus infects the tree. As new growth emerges, additional applications will continue to protect the leaves as they become larger. Typically, three treatments throughout the season provide effective control for crabapple trees in residential landscapes.

If your tree has not been treated, but was infected with apple scab, then you may want to consider deep-root fertilization to improve the overall health of your tree. Deep-root fertilization assures there are adequate nutrients in the soil for the tree to utilize as it needs them.

Although apple scab is often seen as a cosmetic issue, if left untreated, it can significantly impact the long-term health of your crabapple tree, weakening it and making it susceptible to further issues. Regular treatment and maintenance are key to ensuring your tree thrives. Contact Owen Tree & Lawn Care today if you suspect apple scab may be infecting your crabapple tree.