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Diagnosing and Treating Crabapple Leaf Spots and Defoliation

Frogeye Leaf Spot vs. Apple Scab on Crabapples

Brown-spotted, deformed leaves dropping by May suggest frogeye leaf spot (Botryosphaeria) or apple scab (Venturia). Both cause premature defoliation. Control: 3-5 fungicide sprays at 10-14 day intervals from bud break to mid-June. Remove mummified fruit. Fertilize with 2-3 lbs actual N per 1000 sq ft (e.g., 10 lbs 20-5-10). Resistant cultivars best for new plantings.

Trees: Cedar-Apple Rust on Apple Trees: Identification and Management; Maple Leaf Warts and Holes: Phyllosticta Leaf Spot; Crab Apple White Fluffy Growth: Scale or Powdery Mildew?; Lichens on Crabapple: Harmless but Manageable; Phyllosticta Leaf Spot on Young Maple; Eliminating Crabapple Fruit with Florel Growth Regulator; Transplanting Crabapple Seedlings: Root Ball and Timing; Reviving a Wild Apple Tree: Pruning and Care Guide; Managing Fungal Leaf Spots on Tabebuia Trees; Crab Apple Defoliation from Mold: Fungicide Spray — Prevents Repeat

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