Tea blister blight

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
oBlister 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.
oE. 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