Plum
Symptom Cause  
Leaves curled and discolored; honeydew evident on undersides of leaves, sometimes sooty mold forms
Aphids
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Skin pecked and portion of fruit eaten
Birds
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Many holes in trunk and branches; small limbs girdled sawdust at holes
Borers
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Small brown spot; fruit matures and spot enlarges to rot part or all of fruit
Brown Rot of Stone Fruit
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Skeletonized leaves
Cankerworms
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Much foliage is eaten starting from top of tree down
Caterpillar of Tussock Moth
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Ends of twigs die and fall off
Cicadas
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Roots, stems and/or crowns develop tumors (galls); outer layer turns brown and corky.
Crown Gall
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Fruit falls, crescent shaped cuts in fruit
Curculios
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Small misshapen fruits
Fruit Fly Larvae
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Holes in leaves and flowers
Japanese Beetles
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Holes in flowers; leaves rolled up
Leafrollers
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Cottony white masses on roots, stems, branches leaves; reduced plant vigor
Mealybugs
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Fan-shaped plaques of white fungal strands between bark and wood of roots and lower trunk; armillaria mellea
Oak Root Fungus
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Young tree seedlings wilt, roots gnawed, plant dies
Pocket Gophers
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White spots on leaves; eventually entire leaf is covered with powdery substance.
Powdery Mildew
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Orange or brown pustules on leaves
Rust (on plants)
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Weaken plant, stunting growth, fewer blooms and fruit.
Sawflies
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Leaves yellow, drop; bumps on leaves and stems; sometimes sticky material on leaves
Scale
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Black mold on leaves and stems of plant.
Sooty Mold
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Leaves stippled, yellow, dirty; webbing on interior stems of plant
Spider Mites
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Webbed nest in tree branches filled with caterpillars
Tent Caterpillars
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