Corn
Symptom Cause  
Leaves wrinkled or curled; discolored, stunted, tend to fall off
Aphids
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Leaves, stems and buds eaten
Armyworms
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Pale, streaked leaves; yellow, sticky substance exudes from a cut stem
Bacterial Wilt
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Plant gradually wilts, sawdust trail around stalk and ears
Common Stalk Borer
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Worms feeding on tips of ear inside husk; leaves chewed, ragged
Corn Earworms
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Ears malformed, undeveloped kernels; leaves chewed
Corn Rootworm
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Large galls develop on stalk/ears/roots; later, grayish galls blacken/ release spores
Corn Smut
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Holes chewed in leaves, leaf stalk, stems; plant wilts, dies.
Cucumber Beetles
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Plants disappear all or in part
Deer
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Plant gradually wilts, sawdust trail around stalk and ears
European Corn Borers
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Leaves riddled with shot holes; plant weakens
Flea Beetles
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Yellowing of foliage and gradual defoliation; plants may become stunted
Fusarium Ear Rot
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Large holes chewed in leaves
Grasshoppers
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Holes in leaves and flowers
Japanese Beetles
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Plant gradually wilts, sawdust trail around stalk and ears
Lesser Corn Stalk Borer
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Plant stunted/leaves yellowed, root lesions
Nematodes
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Few ears on corn stalks
Poor Pollination
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Ripened ears of corn disappear
Raccoons
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Orange or brown pustules on leaves
Rust (on plants)
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Corn eaten off the ears
Squirrels
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Plant wilts/underground stems/roots chewed.
Wireworms
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