EPWS
310 - PLANT PATHOLOGY
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