Apple Scab Treatments by SavATree Insects & Diseases Photo Credit: William Jacobi, Colorado State University, Bugwood.org Apple scab is a destructive fungal disease affecting apple trees and related species, causing leaf and fruit damage that compromises tree health and harvests. While early symptoms may appear cosmetic, untreated infections lead to reduced vigor, premature leaf drop, and unmarketable fruit. SavATree’s science-backed treatments can help address existing infections and prevent future outbreaks. Signs of an Apple Scab Infection Detecting apple scab early is crucial for preventing widespread damage. Watch for these common signs to keep your trees safe: Olive-green to brown spots: Circular lesions on leaves and fruit that eventually turn dark and develop a velvety texture Leaf distortion: Infected leaves may curl, pucker, or become twisted as the disease progresses Premature leaf drop: Heavily infected trees often lose their leaves by midsummer Fruit lesions: Dark, scabby spots on fruit that may cause cracking and deformation as the fruit grows Reduced fruit quality: Affected fruit is smaller, misshapen, and may drop prematurely Weakened tree vigor: Trees suffering from repeated infections show overall decline in health What Causes Apple Scab? Apple scab infections typically begin in spring when seasonal rain releases fungal spores that have overwintered in fallen leaves. Fungal spores then spread via wind and rain, landing on newly emerging leaves and fruit. The prolonged leaf wetness of spring also allows spores to germinate and penetrate plant tissue, which leaves trees vulnerable to the development and spread of secondary infections. Once established, the apple scab fungus produces new spores that cause repeated infection cycles throughout the growing season. Many commercial apple varieties, such as McIntosh and Cortland, are highly susceptible to scab, while factors like poor air circulation, dense canopies, and improper pruning can increase the impact of the disease. Professional treatment is typically necessary to treat apple scab—especially if infections are severe or recurring. How Does Apple Scab Harm Your Trees? Apple scab infection can negatively impact your trees in several ways, including: Interference with photosynthesis due to leaf lesions and premature leaf loss Reduction in tree vigor and productivity over time Compromising leaf and fruit surfaces, potentially increasing vulnerability to other diseases Significant reduction in fruit quality and marketability Young trees or trees that are already stressed have fewer resources to withstand ongoing damage caused by apple scab, and they are therefore particularly susceptible to these symptoms. Types of Trees and Plants Affected Apple scab primarily affects apple trees, though it can also impact crabapple, mountain ash, pear, hawthorn, and cotoneaster trees. The impact of apple scab on each of these trees can be both unsightly and significantly reduce your landscape's health and vitality, and this is just one of many types of infestations and diseases that can damage your valuable plants and shrubs. That’s why SavATree provides tree disease treatment solutions that target apple scab along with a wide range of other common threats. Where to Find Apple Scab Treatment Near You If you're searching for "spots on apple tree leaves," "how to treat scabby apples," or "treatment for black spots on apples," SavATree's ISA Certified Arborists can help. Our team specializes in identifying and treating apple scab and its symptoms, including unsightly leaf spots, fruit damage, and early leaf drop. SavATree’s certified and experienced arborists develop personalized treatment plans for your property based on the severity of your infection, the tree species affected, your specific site conditions, and environmental considerations. Our integrated plans can effectively manage apple scab when applied early in the season, and our approach includes: Targeted Protective Applications: Protective treatments are timed to coincide with vulnerable growth stages to support the tree's natural defense systems. Cultural practices: Proper pruning to improve air circulation, sanitation of fallen leaves, and appropriate irrigation practices Resistant variety selection: Recommendations for resistant alternatives—including Liberty, Enterprise, Goldrush, and Pristine—when replacing trees Soil health management: Ensuring optimal nutrition to improve tree vigor and natural defense mechanisms Ongoing monitoring: Regular assessments to adjust treatments as needed throughout the growing season SavATree's professional treatments not only address current infections but also help prevent future apple scab problems through ongoing monitoring and maintenance programs. That said, effective management of apple scab depends on three key factors: timing, environmental conditions, and thorough coverage. Your arborist will work to make sure any applied treatments work with maximum efficacy. Protecting your landscape from apple scab preserves the beauty, health, and value of your property. Contact us today to schedule a consultation with an expert arborist.