Diseases of Tea - Symptoms, Pathogenic characters and their Management

PAT 301 - DISEASE OF FIELD AND
HORTICULTURAL CROPS AND THEIR
MANAGEMENT (1+1)
DISEASES OF TEA
Presented By…
Guhan.C, B.Sc.(Hons).Agri,
Id no : 2018033029,
JKKMCAS, Erode, .

Name of the Disease Causal Organism
Blister Blight Exobasidium vexans
Grey Blight Pestalotia theae
Horse hair blight Marasmius crinisequi
Twig Dieback / Stem Canker Macrophoma theicola
Brown root disease Fomes lignosus
Black root disease Rosellina arcuta
Red root disease Poria hypolateritia
Armillaria root rot Armilliaria mellea
Red Rust Cephaleuros mycoides
Crop : Tea
Scientific Name : Camellia sinensis
Family : Theaceae

Blister Blight - Exobasidium vexans
Symptoms :
 Small pale pinkish spots on leaves.
 Upper surface of the spot become light green and depress into a
shallow cavity.
 Lower surface correspondingly forming blister like swelling covered
by white growth of fungus.
 Later stage blister turns dark brown and shrinks to flattened patch.
 In stem, spots without blisters are formed and damages stem, leaves
and bud wither.

Pathogen :
Sexual spores – Basidiospores
Asexual spores – Conidia
 Conidia causes earlier infection.
 Basidia causes drying of leaf.
 Elliptical, bicelled conidia are born at terminal end of hyphae.
 Hyphae aggregates and seen as mass.

Mode of spread :
Primary spread : Basidiospores from infected seedlings from
abandoned nursery.
Secondary spread : Basidiospores from infected plants.
Management :
 Removal of affected leaves and shoots by pruning and destruction of
the same have been recommended.
 Spraying of Bordeaux mixture or Copper Oxy Chloride 0.1%.
 A mixture of 210g of Copper oxy Chloride + 210g of nickel chloride
per ha sprayed at 5 days interval from June to September and October
to November
 Spray Tridemorph at 340 and 560 ml/ha is satisfactory under mild and
moderate rainfall conditions.

Grey Blight - Pestalotia theae
Symptoms :
 Minute brownish spots on older leaves, soon turn grey.
 Spots are irregular and have fine concentric lines.
 Black dots of acervuli seen on older spots.
 Leaves distorted and die back symptom appears.

Pathogen :
 Conidia produced inside the black acervuli amidst sterile setae.
 Conidiophores hyaline, short and simple and bear five celled
conidia.
 The middle three celled are dark coloured while the end cells are
hyaline with 3-5 slender elongated appendages at the apex of the
spore.

Mode of spread - conidia from infected plants.
Management :
 Avoid plant stress.
 Grow tea bushes with adequate spacing to permit air to
circulate and reduce humidity and the duration of leaf wetness.
 Spray Copper Oxy Chloride or Bordeaux mixture 0.1% during
winter season and Summer season.

Twig Dieback / Stem Canker - Macrophoma theicola
Symptoms :
 The first symptoms include browning and drooping of affected leaves.
 As the disease spreads into the shoots, they become dry and die.
 The entire branch can die from the tip downward.
 Dying branches often have cankers—shallow, slowly spreading lesions
surrounded by a thick area of bark.

Management :
 Plant in well draining, acidic soils.
 Remove diseased twigs by cutting several inches below cankered
areas and disinfecting them.
 Spray appropriate protective fungicides during periods of wet
weather or natural leaf drop to protect leaf scars from infection.

Horse hair blight - Marasmius crinisequi
Symptoms :
 Black fungal threads resembling horse hair are attached to upper
branches and twigs by small brown discs.
 The fungus penetrates and infects the twigs from the discs and
produces volatile substances that cause rapid leaf drop.
Management :
 Remove a and destroy all crop
debris from around plants.
 Prune out infected or dead
branches from the plant canopy.

Brown root rot - Fomes lignosus
Symptoms :
 The roots of the tea bush are encrusted with a mass of earth and small
stones cemented to the root by the mycelium.
 Mode of spread - Rhizomorph and
root contact.

Black root disease - Rosellina arcuta
Symptoms :
 Black strands adhere to the roots as loose cob – webby mass.
 Star like sheets of white mycelium on the collar region.
Mode of spread - Rhizomorph and root contact.

Red root disease - Poria hypolateritia
Symptoms :
 Flat, black, rhizomorph on infected portion.
 Branched markings on the surface of the wood.
 Root mottled appearance of red and white.
 Bark softened and wood discoloured as
bluish black.

Armillria root rot - Armillaria mellea
Symptoms :
 Bushes wilt and turn chlorotic, affect collar region; Bark cracks.
 Sheets of creamy coloured mycelium accompanied by flattened
brown rhizomorph.
 Sporophores produced on collar region, death of whole plant.

Pathogen :
 Flattened brown rhizomorphs are produced.
 Basidiospores from the sporophore infect the host.

Management of Root diseases:
 Removal and destruction of infected plant.
 Clean cultivation with out fallen leaves
 Dig a drench around the infected bush to provide sunlight in the
drench which prevent the spread of mycelium.
 Soil fumigation is the best method.
 Application of Vepam and Metham Sodium 20-25cm apart from
collar of root to avoid phytotoxicity.

Red rust - Cephaleuros mycoides
Symptoms :
 It is an algal parasitic or epiphytic.
 Orange yellow, roughly circular patch on the upper surface of the
leaf.
 The penetrating filament may extend laterally between epidermis
and adjacent layer.

Pathogen :
 The algae produces sporangia on sporangiophore.
 Sporangia produce numerous zoospores.
 5-8 sporangia are formed on each vesicle.
 Zoospores are involved in the disease spread.

Mode of spread - zoospores from infected plants.
Management :
 Avoid plant stress.
 Avoid poorly drained sites.
 Promote good air circulation in the plant canopy to reduce
humidity and duration of leaf wetness.
 Removal of infected portions by spraying of Bordeaux mixture.
 Destruction of affected plant portions.
 Improving the nutrient status of the soil by application of NPK.

Diseases of Tea - Symptoms, Pathogenic characters and their Management

Diseases of Tea - Symptoms, Pathogenic characters and their Management

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Diseases of Tea - Symptoms, Pathogenic characters and their Management

Similar to Diseases of Tea - Symptoms, Pathogenic characters and their Management (20)

More from VisanthGuhan

More from VisanthGuhan (8)

Recently uploaded

Recently uploaded (20)

Diseases of Tea - Symptoms, Pathogenic characters and their Management