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Flowering Crabapple Yellow Spots: Leaf Spot Fungus Management

Brown spots with green halos on yellowing crabapple leaves = leaf spot fungus. Newly transplanted trees are stressed and vulnerable.

Cultural Controls (Do Now)

Rake and destroy all fallen leaves—reduces overwintering spores.
Mulch 3 inches, off trunk.
Fertilize this fall: 10-10-10 at 1 lb per inch trunk diameter before rain.

Chemical Control (Next Spring)

Spray protectant fungicide (chlorothalonil, copper, mancozeb) at bud break, repeat 7–14 days later. Timing is critical—sprays after symptoms appear don't cure.

Healthy trees tolerate leaf spots; stressed ones decline. Your tree was stressed by transplant + rabbit bark damage (now wired). Fertilize and sanitize.

Trees: Caragana Yellow Leaves: Overwatering Diagnosis; Maple Leaf Spot: Phyllosticta—Mostly Cosmetic; Maple Petiole Borer: Natural and Self-Limiting; Nepenthes ventricosa Yellowing Leaves: Natural Aging or Issue?; Nepenthes Lower Leaves Yellowing: Normal Aging & Light Response; Propagating Drosera capensis from Leaf Cuttings: Correct Method; Yellowing Nepenthes ventricosa: Normal Color or Problem?; Petunia Yellow Leaves: Four Causes and Targeted Fixes; Gardenia Yellowing Leaves: Whiteflies, Aphids, or Overwatering; Tomato Yellowing Then Browning: pH, Fertilizer, or Water Diagnosis

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