Plantation Crops

Plant protection

Plant protection in tea
Tea is grown as monoculture under varying agroclimatic conditions, remote from its natural environment. Hence, they are prone to the attack of many pests and diseases. Important ones are listed here under
Diseases of tea: Diseases due to fungi, bacteria, virus, animal parasites , physiological disorder and mechanical damages are observed.
Bacterial and viral diseases are not that problematic in tea when compared to fungal and algal diseases under Indian conditions
A) Leaf diseaseas
1) Blister blight: Cause : Exobasidium vexans ( a fungal disease) :
2) Black rot:
B) Root diseases:
Blister blight disease of tea and its control

A) Leaf disease
1) Blister blight: Cause : Exobasidium vexans ( a fungal disease) :
It is commonly found fungi in South India, Darjeeling and Assam but moderate in Himachal Pradesh. This disease is endemic to the growing areas of Asia. It has been reported from almost all tea growing regions of India. The disease is more severe in South Indian plantations than that of North East Indian tea plantations
Congenial conditions for disease spread : Cool, Moist an relatively still air favors infection.

Symptoms:

1) Presence of blisters on upper leaf surface & young shoots : Formation of circular or oval translucent spots. The spots become depressed forming a concave blister on the infected upper surface of leaves.
2) Convex under surface of leaves : Undersurface of leaves will produce convex surface and it becomes grey and finally white
3) Death of shoots :

Control measures:

Chemical control:
1) Application of copper fungicides i.e., COC @ 0.25 per cent.
2) Systemic fungicide: Calixin (Tridemorph 50 EC) best control. @ 1 ml per litre of water (0.1%).
3) Pruning schedule: Pruning operation should be shifted to dry weather period for minimum infection.