Tea blister blight

1. COLLEGE OF AGRICULTURAL TECHNOLOGY
(Affiliated to Tamil Nadu Agricultural University, Coimbatore-3)
Kullapuram (Po),ViaVaigai Dam, Theni-625 562
TEA BLISTER BLIGHT
STUDENT COURSE TEACHER
VIMALA V Dr. PARTHASARATHY. S
2015021138 Asst. Prof. (Plant Pathology)

2. Disease Name: Tea Blister blight
Pathogen Name: Exobasidium vexans
Common Name:Blister Blight
Hosts: Tea

3. Systematic Position
Kingdom : Fungi
Phylum : Basidiomycota
Class : Exobasidiomycetes
Order : Exobasidiales
Family : Exobasidiaceae
Genus : Exobasidium
Species : E. vexans

4. History and Diversity
o Blister Blight of tea, a leaf disease caused by the
fungus Exobasidium vexansMassee, occurred for the
first time in Ceylon in October 1946 and spread
rapidly through a large tea area.
o E. vexans is the most economically significant tea
pathogen in many countries, causing up to 50% crop
yield loss when uncontrolled. (Mur et al. 2015, Ajay
et al. 2009)

5. Pathogen description
Basidia are hyaline, club shaped, thin walled with 2
short sterigmata at the end and arise from the
hymenial layer intermingled with sterile hairs.
Each basidium bears 4-8 hyaline and oval to oblong
basidiophores.
Ocassionally the basidiospores form hyaline,
elliptical, straight /slightly curved conidia like
blastophores which also germinate and infect the
leaves.

7. Symptoms:
• Small, pinhole-size spots are initially seen on young
leaves less than a month old.
• As the leaves develop, the spots become transparent,
larger, and light brown.
• After about 7 days, the lower leaf surface develops
blister-like symptoms, with dark green, water-soaked
zones surrounding the blisters.

8. • Following release of the fungal spores, the blister
becomes white and velvety.
• Subsequently the blister turns brown, and young
infected stems become bent and distorted and may
break off or die.

9. https://upload.wikimedia.org/wikipedia/commons/b/ba/Exobasidium_vexans2.jpg

10. Spread of disease
Mode of survival:
The basidiospores have a low survival rate
under conditions of drought or bright sunlight.
Mode of spread:
The spores are readily dispersed by wind.

11. Epidemiology:
The disease cycle repeats continuously during
favorable (wet) conditions

12. Management
• Removal of affected leaves and shoots by pruning and
destruction of the same have been recommended.
• Spray Bordeaux mixture 1% 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