OH. 



170 DISEASES OF TROPICAL PLANTS 



Loranthus pentandrus in India. 

 Struthanthus marginatus, Desr. 

 Phoradendron crassifolium, (Pohl.) Eichl. 



TEA 



Grey Blight. This disease is due to the fungus 

 Pestalozzia guepini, 1 Desmaz. This very destructive 

 and most common fungus blight first appears as small 

 greyish spots on the upper surface of the older leaves, 

 which increase in size and finally coalesce, thus form- 

 ing large irregular blotches which frequently cover the 

 greater part of the leaf. The blotches are grey, bounded 

 by a dark line, and when mature are sprinkled with 

 black fruiting bodies. The leaves finally assume a 

 blistered or swollen appearance, and eventually the 

 cuticle over these blisters bursts, usually forming a 

 triangular figure Y and allowing the greater number of 

 conidia to escape. The spores are carried by the wind, 

 and for that reason frequently start on one side and 

 gradually spread over the entire plant. The disease 

 frequently starts on one side of a number of plants in 

 a definite area, and gradually spreads in the direction 

 of the prevailing winds. The fungus may attack the 

 petiole or base of the leaf, causing it to turn brown and 

 fall without showing the distinctive character of the 

 disease. It sometimes causes an epidemic, and at other 

 times attacks only the weakened plants. It is most 

 severe on poorly-drained sour land, and its spread is 

 facilitated by the presence of the red spider. The 

 disease has been reported from Europe, United States, 

 India, Assam, Ceylon, New Zealand, Australia, and 

 other places. It is probably very widely distributed 

 throughout the tea-growing countries. It also attacks 

 Camellia and Rhododendron in India, Citrus and 

 Magnolia in the United States, Niphoblous in New 

 Zealand, and Amphitomia in Queensland. The most 



1 Pestalozzia guepini, Desmaz. Synonyms Pestalozzia inquinans, Karst. ; 

 Pestalozzia camelliae, Pass.; Coryneum camelliae, Mass.; Hendersonia theieola, Cke. 



