102 VEGETABLE PARASITES AND EPIPHYTES 



elevation as many as 95 per cent, of the fruits were 

 attacked. When the young fruits are infected their 

 growth is arrested as the disease develops and the beans 

 are not matured. The fruit turns brown, the tissues de- 

 compose, and they may fall to the ground or remain on the 

 tree and infect healthy fruits. When the disease attacks 

 a fruit at a later stage it may grow to its normal size and 

 be harvested with properly matured fruits ; it differs 

 from them, however, as both the enveloping mucilage and 

 the integuments are usually dried up and sour smelling. 

 Once a fruit has been infected with the disease there 

 appears to be no means of checking its spread. The 

 importance of burying diseased fruit shells and fruits 

 which have been destroyed by the fungus previous to 

 maturation cannot be too much insisted on. 



When the shade is too dense this should likewise receive 

 attention. 



Good results are reported to have attended the spray- 

 ing experiments carried out at the Experiment Station, 

 Peradeniya, Ceylon, to check a fungus disease of cocoa 

 fruits. The following table, taken from the 1907 Report 

 of the Ceylon Botanical Department, demonstrates the 

 reduction in the number of diseased fruits harvested. 



Bordeaux Mixture was the fungicide employed, and 

 the same report shows that the fruits on 196 acres of 

 cocoa trees were sprayed at a total cost for labour of 

 82' 6 Rs. (£5 10s. IJrf.), or an average cost of 6jd. per 

 acre. 



Witch-Broom Disease, CoUetrotrichum luxiferum. — This 



