Fungi Lecture 3: Symptoms of fungal diseases

A. Symptoms of fungal disease (Pages 105-122)

Fungal diseases can be grouped according to symptoms, but note that more than one fungus can cause the same symptom!

Symptoms refer to changes in the infected or diseased plant or plant tissue. Signs refer to actual fungal structures such as mycelium, spores (conidia, sporangiospores etc.) etc which is found on the plant.

Note that symptoms should not be used for diagnosis but that signs may be used with more confidence.

Leaf Spots - Localized lesions on leaves dead or collapsed cells usually brown or black

Blights - General and rapid browning and death of leaves, branches, twigs and flowers

Cankers - A localized necrotic (dead) lesion on the stem or trunk of a woody plant, usually black or brown, cracked and sunken.

Dieback - Necrosis of twigs and branches going from distal to proximal end

Root rot - Rot of any or all parts of a root system

Damping off - Rapid collapse and death of young seedlings in the field due to fungal pathogenesis

Basal stem rot - A rot of the lower part of the stem

Soft Rots - A wet rot and maceration of fruits, roots, bulb , tubers or leaves

Dry Rot - A dry, cracking rot of plant parts (as above)

Anthracnose - A necrotic, sunken ulcer-like lesion on stem, fruit, leaves or flowers, usually black and not cracked

Scab - local lesions on fruit, leaves, tubers ,usually raised or sunken but often light (or different) in color giving a scabby appearance.

Decline - Poor growing plants often chlorotic, partly defoliated, with small, brittle leaves.

Wilt - loss of turgor and drooping of leaves due to disturbance to vascular system

Rust - sori of rust fungi on leaves, stems and flowers

Mildew - Chlorotic, necrotic areas on leaves, stems, fruit and flowers with fungal mycelia and spores covering the surface

Hyperplasia/Hypertrophy (abnormal division/enlargement)


Clubroot - Swollen stubby roots giving the appearance of clubs

Galls - Globose swellings on leaves and stems

Warts - Wart like protuberances on stems and fruits

Witches' broom - Profuse upward branching of twigs and distorted leaves

Leaf curl - Distortion, thickening and abaxial curling of leaves

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