LOSSES THROUGH " WITCH-BROOM " DISEASE 103 



disease is also due to a fungus parasite ; it has caused 

 serious damage in Surinam cocoa plantations, and has 

 also been found on cultivated cocoa trees in British 

 Guiana and Trinidad. The extent of the losses sustained 

 by the ravages of this pest in Surinam may be estimated 

 by the falling off of the cocoa crop from 1,290 tons in 

 1895 to 464 tons in 1899. The popular name of this 

 disease is due to the hypertrophied growths that it 

 induces ; which in conjunction with the numerous 

 lateral branches, formed in clusters, resemble small 

 brooms. Fruits are also affected by it ; these do not 

 develop to a normal size, but become indurated. The 

 parasite responsible for this disease was originally de- 

 scribed as Exoascus Theobromce, Ritz Bos, but the more 

 recent and extensive researches of Van Hall and Drost 

 in Surinam have proved that it is due to an entirely 

 different fungus, i.e. Colletrotrichum luxiferum. The 

 following information on this subject has been extracted 

 from Fredholm's translation (Proceedings of the Agri- 

 cultural Society, Trinidad) of the report of these two 

 investigators. 



The first symptoms of the disease are usually the 

 abnormal development of shoots, which are generally 

 from two to six times as thick as healthy ones, in con- 

 junction with a strong tendency to produce side shoots 

 and leaves which remain soft and flimsy. On diseased 

 twigs the buds begin to grow before they have 

 matured ; they seldom bear leaves themselves, but are 

 supported at the base by an abnormal leaf. Some 

 trees have been observed which did not carry a single 

 healthy twig. 



The texture of the " witches'-brooms " is herbaceous 

 and fleshy, and they never become woody. The growths 

 develop quickly, but their life is short, drying from the 

 base upwards and dying in about two weeks. Severely 

 attacked trees are covered with " witches'-brooms " ; 

 when these latter die, infection of the tree by wound 

 parasites is facilitated, and Thyridaria tarda, the "die- 

 back " disease previously described, is commonly met 

 with on such trees. 



In addition to the induration of the fruits which the 

 disease occasions, the fruit-stalks and even the fruits 

 themselves may be hypertrophied. In the latter case 



