Look for these diseases when monitoring
fields for spider mites. Flag locations with problems so you
can follow up with more monitoring or control action. Names link
to more information on identification and management.
Click on photos to enlarge
Angular leaf spot lesions
Identification tip: Watersoaked lesions on underside
of leaf, delimited by leaf veins; dark, viscous fluid on
surface of lesions.
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Angular leaf spot coalesced lesions
Identification tip: Reddish brown spots and patches on upper leaf surface.
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Anthracnose runner lesions
Identification tip: Sunken, dark brown lesions on
stems, runners, leaf petioles.
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Anthracnose damaged plant
Identification tip: Wilted, collapsed plants.
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Anthracnose crown discoloration
Identification tip: Red-brown discoloration in crown tissue of wilted
plants.
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Common leaf spot lesions Identification
tip: Leaf spots with light brown centers and
dark brown margins.
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Common leaf spot coalesced lesions
Identification tip: Multiple leaf spots
converge into dark patches; leaves may be killed.
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Leaf blotch lesion
Identification
tip: Tan or light brown patches at leaf margins;
numerous dark brown dots in the discolored areas.
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Phytopthora crown rot damage
Identification
tip: Wilted, dying plants.
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Phytophthora crown rot
Identification tip: Brown discoloration of crown
tissue.
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Red stele root rot
Identification
tip: Roots rotted back from tip; reddish brown
discoloration of central conducting tissue above rotted portion.
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Powdery mildew damage
Identification tip: Leaf edges curled upward; purple discoloration
of leaf margins.
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Powdery mildew sporulation
Identification tip: Powdery white patches on underside of
leaves .
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