Symptoms of plant diseases
Symptoms are the external and
internal reactions or alterations of a plant as a result of a disease.
Anthracnose
Anthracnose of mango | Anthracnose of chilli |
Anthracnose is recognized by necrotic and sunken ulcer-like lesions on the stems, leaves and fruits.
Anthracnoses are caused by fungal pathogens.
Anthracnoses are caused by fungal pathogens.
Examples
- Anthracnose of mango caused by Colletotrichum gloeosporioides var minor.
- Anthracnose of chilli caused by Colletotrichum capsici.
Blight
Leaf of taro showing Blight |
Blight is characterized by extremely rapid browning and death of leaves, branches, twigs and floral organs. Blight affected foliage collapse. In warm climate blight affected plants appear as if these are burned.
Examples
- Late blight of taro caused by Phytophthora colocasiae.
- Late blight of potato caused by Phytophthora infestans.
- Early blight of potato caused by Alternaria solani.
Blotches
Red rot affected stem of sugarcane showing blotches |
A disease characterized by large, irregularly shaped, unpleasant spots or blots on leaves, shoots and stems.
Examples
- Red rot of sugarcane caused by Colletotrichum falcatum .
Canker
Citrus fruits showing canker |
Cankers are localized, necrotic lesions on stems leaves and fruits.
Examples
- Citrus canker caused by Xanthomonas axonopodis pv. citri.
Chlorosis
Yellowing of normally green tissue (particularly, leaves) due to chlorophyll destruction or failure of chlorophyll formation. Chlorosis is common symptom in viral diseases of plants.
Curl
Distortion, thickening, shirking and curling (upward and downward) of leaves and or petioles.
Curl is the common symptom of viral diseases.
Curl is the common symptom of viral diseases.
A growing shoot showing symptoms of leaf curl |
Examples
- Leaf curl of papaya caused by Papaya leaf curl virus (a DNA virus)
Damping off
Rapid death and collapse of
very young seedlings. Fungus degrades the cell wall and middle lamella (cementing material between plant cell). Due to which affected root and stem lose the mechanical strength and plants collapse from just above the ground and die.
Downy mildew
Downy mildew of cucurbit |
Downy mildews appear as chlorotic and necrotic angular lesions on the leaves. This gives burned appearance of leaves and sometimes referred as 'wildfire'. The disease is devastating in the cucurbits.
Examples
- Downy mildew of grapes caused by Plasmopara viticola
- Downy mildew of cucurbits caused by Pseudoperonospora cubensis
Galls/Wart
Stem gall of coriander |
Galls are the abnormal growth in roots, stem, leaves, inflorescence and fruits. Galls are produced as a result of hyperplasia and hypertrophy, which are induced by fluids secreted by insects and their eggs. Insect induces the gall for their own benefit to protect the eggs.
Examples
- Foliar gall in Alstonia scholaris caused by Pauropsylla tuberculate.
- Foliar gall in mango caused by Erosomya mangiferae.
- Stem gall of coriander caused by Protomyces macrosporus.
Hypertophy and Hyperplasia
Irregular enlargement in size of cells of any plant organs (stems, leaves, blossoms, roots) is called as hypertrophy. Irregular and abnormally increased cell division in any plant organs (stems, leaves, blossoms, roots) is called as hyperplasia. Hypertrophy and or hyperplasia eventually induce the gall/wart formation. In floral parts these activities result in phyllody.
Examples
- Phyllody is induced due to 'hypertrophy' and 'hyperplasia' in white rust of crucifers caused by Albugo candida
Little leaf
Reduction in the size of leaf lamina is called as 'little leaf'. These are induced by phytoplasma.
little of brinjal |
Examples
- Little leaf of brinjal caused by phytoplasma.
Malformation
Malformation in shoot of mango | Malformation in inflorescence of mango |
Enlarged portions of plant organ (stems, leaves, blossoms, roots) is called as malformation. Malformation in young apex ceases the apical growth and plants become stunted.
Examples
- Mango malformation disease caused by Fusarium moniliforme var. subglutinans.
Necrosis
When a cell or tissue die and degenerate, it is termed as necrosis. The necrotic portion of the plant darken and wilt.
Phyllody
Head of bajra showing phyllody |
Phyllody is the abnormal development of floral parts into leafy structure. Excessive production of leaves in place of shoots and blossoms is known as phyllody. Phyllody is induced by hypertrophy and hyperplasia. Phyllody is more common in the diseases caused by mycoplasma and viruses. Some of the fungal diseases also induce phyllody in plants.
Examples
- Little leaf of brinjal caused by mycoplasma.
- Green ear disease of bajra caused by scleroscpora graminicola.
- white rust of crucifers caused by Albugo candida.
Powdery mildew
Powdery mildew on akarkarha leaves |
Powdery mildews are the superficial growth of fungal mycelia and their reproductive structures on leaves of infected plants. Powdery mildew appear as powdery, cottony mass on one or both the surface of leaves.
Examples
- Powdery mildew of cucurbits caused by Sphaerotheca fuliginea.
Scab
Localized lesions on host fruit, leaves tubers, etc are called as scab. Scabs are usually raised or sunken and cracked.
Scabs on fruits of apple |
Examples
- Scab of potato caused by Streptomyces scabies.
- Scab of apple caused by Venturia inaequalis.
Spot
Tikka disease showing spots on leaves |
Localized lesions on host leaves and fruits consisting of dead and collapsed cells are called as spots. Spots are most common in the fungal diseases. Spots are often black colored with various shapes and sizes.
Examples
- Leaf of mustard caused by Alternaria brassicae.
- Leaf spot disease of groundnut caused by Cercospora arachidicola and C. personatum.
Rust
Stem rust of wheat |
Rusts are the powdery pustules on the leaves, stems and fruit. The color of rust is highly variable among the various diseases. These appear as red, brown, black, yellow, orange. Rust is the powdery mass of fungal spores (often uredospores and teliospores). Most of the rust diseases are caused by fungi of order Pucciniales. Among which, genus Puccinia is more common.
Examples
- Black or stem rust of wheat caused by Puccinia graminis f. sp. tritici.
- Rust of beans caused by Uromyces appendiculatus.
- Red rust of mango caused by Cephaleuros virescens (an alga).
Smut
Infected inflorescense of doobgrass showing typical symptoms of smut disease |
Smuts are characterized by black soot or dirt like powder consists of fungal chlamydospores. Smuts are caused by fungi belonging to order Ustilaginales. Smut appears on the grains, which are transformed in to black mass of powder.
Examples
- Loose smut of wheat caused by Ustilago tritici.
- Covered smut of wheat caused by Ustilago hordei.
- False smut of rice caused by Ustilaginoidea virens.
- Loose smut of barely caused by Ustilago nuda.
- Smut of doob-grass caused by Ustilago cynodontis.
Wilt
Wilt of chilli caused by Fusarium oxyporum f. sp. capsici. |
Wilt disease is marked by generalized loss of turgidity
and drooping of leaves or shoots and rapid death of whole plants. Wilt affects the vascular bundles of the plants and chokes the xylem vessels. Wilt are caused by Fusarium spp.
Examples
- Wilt of arhar caused by Fusarium oxyporum f. sp. udum.
- Wilt of chilli caused by Fusarium oxyporum f. sp. capsici.
Warts
Wart are rounded excrescences or protuberances on
tubers and stems of plants.
Examples
- Wart disease of potato is caused by Synchytrium endobioticum.
Witches' broom
Witch's broom |
Witches' broom is a deformity in the branching and shape of leaves in plants where a dense mass of shoots with small leaves grow from a node resembling a broom. witches' brooms in plants are caused by phytoplasmas.
Examples
- Witches' broom of jujube caused by phytoplasma.
Vein clearing and vein banding
Ageratum leaves infected with yellow vein mosaic virus showing vein clearing and vein banding |
Vein clearing is the entire disappearance of chlorophyll throughout the networks of veins.
Examples
- Yellow vein mosaic (vein clearing) of bhindi caused by yellow vein mosaic virus.
Vein banding is marked by the white and green areas in between the veins of the leaves.
Examples
- Yellow vein mosaic (vein clearing) of bhindi caused by yellow vein mosaic virus.
Content first created on 20-05-2020
last updated on 23-09-2024
last updated on 23-09-2024
6 Comments
Thank you ma'am.
ReplyDeleteIt's very useful
Very useful, specially photographs:)
ReplyDeleteUseful resources
ReplyDeleteNice collection of diseases pics. Go ahead!
ReplyDeleteVery useful content on symptoms of plant diseases.
ReplyDeleteThank you
DeleteLeave your comments here.