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Blister Blight of tea

Blister blight of tea

What is the causal organism of blister blight of Tea?

Fungus called Exobasidium vexans

What are the symptoms of blister blight of Tea?

Folowing are the symptoms of blister blight of tea

1. Small pale or pinkish circular spots appear on leaves and attain a size of 2.5 cm diameter

2. The spots in the upper surface of the leaf becomes light brown in color and depressed while in under surface of leaf it bulges farming a blister like swelling

3. Lower budget portion is covered with a white powdery growth of fungus

4. When many spots coursers, curling of leaves will occur

5. When it spreads to young succulent stems affected portion are withered

6. The leaf yield is reduced vigor of the tea bush is affected

What are the characteristics of fungus causing blister blight of Tea?

Fungus is the causal organism.

The mycelium is confined to the blistered areas on the leaves

They are septae and collect in bundles below the lower epidermis

Later by rupturing the epidermisa continuous layer of vertical hyphae are projected on the surface of spot

The fungus produces two kind of spores viz.,the conidia and basidiospores

The conidia are most abundant, borne singly at the tip of long stalks

Basidia are formed on the surface in large number but never form a continuous hymenium

What is the Mode of spread and survival of fungus

The fungus completes its life cycle in 11-28 days and several generations of spores are produced in a season

It produces conidia and basidiospores in the same blister

Spores are air borne

The perpetuation of the fungus appears to be form the pre existing infected bushes

What are the Management measures of blister blight of tea?

1. Removal and destruction of the affected portion

2. Spraying with Copper oxychloride 0.25 % in effective

3. Spray with 210 g of COC + 210 g nickel chloride/ha at 5 days interval from June – September and 11 days interval in October – November gives economic control

4. Spraying with systemic insecticides like Atemi 50 SL at 400 ml/ha (or) Baycor (300 EC) at 340 ml/ha a weekly interval is also effective

5. Chlorotalonil, Bayleton, tridemorph is also effective

6. Tridemorph at 340 and 60 ml/ha is satin factory under mild and moderate rainfall condition

References

www.wikipedia.com

Plant pathology – G N Agrios