45 



DISEASES OF CULTIVATED PLANTS 



** 



Spores \-many-septate 



PESTALOZZIA (De Not.) 



Pustules minute, erumpent ; conidia oblong, 2-many-septate, 

 central cells coloured, end ones hyaline, apical cell bearing 

 T-many hair-like appendages. 





v 



/ 



/ 









Fig. 137. Pestalozzia guepini. 1. blotches caused by 



the fungus on a ton leaf; 2, conidia of fungus, highly mag. 



Grey blight of tea plant {Pestalozzia guepini, Desm.) is 

 said by Sir George Watt to be one of the most destructive 

 and dangerous parasitic fungi that attack the tea plant. It 

 occurs in Assam and Cachar, and probably wherever tea is 

 grown in India and Ceylon. The disease first appears as 

 minute, brownish grey spots on the upper surface of the leaf; 

 these spots gradually increase in size and often coalesce, 

 forming large, irregular blotches which become grey, and are 

 sprinkled with minute, black points, the fruit of the fungus. 

 During the increase in size the blotches are often bordered 

 with a dark, slightly raised line. Diseased leaves are not at 

 all blistered or swollen, in fact the diseased patches shrink a 



