VI 



TEA 175 



black dots. The alga appears first, causing the red 

 spots referred to above. It makes a depression in the 

 leaf but does not penetrate the epidermis, as is said to 

 be the case with Cephaleurus mycoidea. It reproduces 

 by means of zoospores, which are especially abundant in 

 the rainy season. 



In its second stage the alga is attacked by a fungus, 

 which results in the death of the alga if young, but if 

 well advanced, in the formation of a lichen. It fruits 

 abundantly by means of conidia, pycnidia, and peri- 

 thecia. In the lichen stage it becomes fused with the 

 cuticle of the host plant, and in some cases pierces the 

 cuticle, but it cannot be considered strictly parasitic. 

 Its greatest injury is due to the reduction of light, and 

 thus the interference with the physiological activities of 

 the host plant. 



The injuries may be reduced by proper drainage of 

 the land, and fertilization, and by cutting and burning 

 the diseased parts. The dead wood should not be 

 allowed to remain on the plant. (7. minimus, Karsten, 

 is a similar organism which attacks and causes consider- 

 able injury to Zizyphus jujuba. 



Canker. This disease is caused by the fungus 

 Nectria ditissima which lives just below the bark of 

 the stems. It gains entrance through wounds and 

 spreads in both directions from the point of attack, 

 finally coming to the surface through ruptures in the 

 bark and producing an abundance of spores which are 

 carried by the wind and by insects. This disease is 

 well kuown in various parts of the world, attacking the 

 apple, the cocoa, the coffee, and the cinchona. All 

 diseased parts should be cut and burned, and all wounds 

 should be painted with tar, white lead, or other dis- 

 infectant. 



Horse-Hair Blight. This is a fungus disease caused 

 by Marasmius sarmentosus, Berk. It has been reported 

 from India, where it also attacks the Terminalia 

 tomentosa and other jungle trees. The plants become 

 covered with masses of fungi which resemble horse hair. 



