Crabapple, Flowering
Symptom Cause  
Foliage curls; puckers; turns yellow; leaves distorted; fall off
Aphids
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Sunken lesions on stems and trunk
Bacterial Canker
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Low flower and fruit production
Biennial Cycle
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Holes drilled in the trunk/branches; girdling of smaller branches; sawdust at holes
Borers
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Trees defoliated, brown egg cases appear on trunk.
Caterpillar of Gypsy Moth
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Young portions of foliage disappear, young tips disappear, bark peeled off
Deer
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Flowers and leaves wilt; bark cankered
Fireblight
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Leaves covered with white powder
Powdery Mildew
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Bark at base of trunk and roots gnawed
Rodent Injury
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Powdery orange spots on leaves
Rust (on plants)
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Dead spots on leaves; shoots blighted
Scab, Apple
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Leaves and branches encrusted with small bumps; stunted plant growth
Scale Insects
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Leaves stippled yellow or bronze; dry out and drop; may be webbing visible
Spider Mites
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