BLISTER BLIGHT OF TEA PLANT 169 



ment of India, says of the present parasite: 'One of the 

 very worst blights on tea is known to the planters as 

 Blister blight. I have seen hundreds of acres completely 

 ruined by it.' 



The fungus attacks the leaves, first appearing as a 

 minute pink spot, which continues to increase in size ; the 

 upper surface of the leaf at this point becomes depressed, 

 forming a circular pit, a corresponding bulging out appear- 

 ing on the under surface of the leaf at the same point. 

 Several of these warts or blisters frequently form on a leaf. 

 The convex surface of the blister eventually presents a 

 minutely velvety or woolly appearance, due to the forma- 

 tion of the fruit of the fungus on the surface of the blister. 

 The first fruit consists of small, one-septate conidia, which 

 often commence germination in situ. These are followed 

 by basidia, usually bearing two spores each. Some- 

 times fruit is also produced on the concave side of the 

 blister. 



When the disease has gained a foothold on the leaves, 

 it also frequently attacks young shoots. 



PREVENTIVE MEANS. Dr. Watt states that the disease 

 'invariably appears on tea that has not been pruned in the 

 autumn. About April it extends to the pruned tea, which 

 has by then come into leaf.' As to whether it would not 

 be wise under the circumstances to prune all plants, lack 

 of practical knowledge prevents me saying ; however, the 

 statement suggests that the mycelium is perennial in the 

 branches, and produces the first crop of spores the follow- 

 ing season, which are carried by wind to the pruned 

 trees. In addition to collecting and burning diseased 

 leaves, it is absolutely necessary to cut off all diseased 

 branches. 



