Citrus
Symptom Cause  
Lesions on rind, black, brown, hard, sunken, black fruiting bodies
Anthracnose (on plants)
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New leaves cupped, curled thickened, honeydew may be present.
Black Citrus Aphids
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Firm brownish patches on trunk base; gummy deposits on trunk bark
Brown Rot Gummosis
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Fruit splitting
Changes In Soil, Humidity, Temp., Fertilizer
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Branch wilts, loses color, dies, white insects.
Citrus Mealy bug
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Silvery scratching, upper leaf surfaces; leaves brown, drop. Fruit yellows.
Citrus Red Mite
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Rusty, rough patches on fruit skin
Citrus Rust Mites
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Raised, corky areas on fruit; leaves, deformed, twisted, falls early
Citrus Scab
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Leaf buds shrivel, brown; leaves turn gray, leathery, curled, distorted
Citrus Thrips
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Small flying white insects when disturbed. On underside of leaves. Leaves and stems with black film or mold.
Citrus Whitefly
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Cottony masses on leaves, stems, branches; foliage wither, turn yellow; leaves, fruit drop; honeydew present
Cottony Cushion Scales
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Yellow blister spots on leaves, brown, turn greasy
Greasy Spot
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Small rotten spot, hole on fallen fruit
Larvae of Caribbean Fruit Fly
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Firm, light brown spots on rind, white mold develops, fruit drops, leaves, twigs may die,
Lemon Brown Rot
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Tree defoliated
Naval Orange Worm
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Leaves chewed or eaten
Orange Dog Caterpillar
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Larva rolls leaves into web; oranges drop
Orange Tortrix Caterpillar
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Small, smooth bumps of plant parts, colored by type of scale; may kill leaves and twigs where located; some on fruit
Scale
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Black mold on leaves and stems of plant
Sooty Mold
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Foliage wilting, dieback, water sprouts develop
Various Blights
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