182 DISEASES OF TROPICAL PLANTS CH . 



young plants the main shoot is frequently affected and 

 the tree killed very quickly. 



The fungus is a wound parasite, and is both parasitic 

 and saprophytic. It is most severe on weak trees, and 

 in low, poorly drained localities. 



The diseased trees should be carefully pruned, and 

 all wounds, from whatever cause, should be painted 

 with tar or white lead. Burn or bury all prunings 

 and all diseased fruits and husks. Cultivate and 

 fertilize in such manner as will ensure healthy trees. 



Scabby Pod. This disease has been attributed to 

 Lasiodiplodia sp., and may be due to Lasiodiplodia 

 theobromae. It appears in the form of small, irregular, 

 scabby, brownish black corky areas over the surface of 

 the fruit. Microscopic examination reveals the presence 

 of the mycelium just beneath the surface. Both the 

 pods and the beans are small, and the beans of a very 

 poor quality. This disease has been reported from 

 Granada, Surinam, and Dominica, but is said to do very 

 little damage. 



Witches' Brooms. The so-called witches' brooms are 

 malformations which may be due to many causes. They 

 are more or less common on both forest and cultivated 

 trees in many parts of the world, and are known by the 

 Dutch names of " Krullotemplaag," " Heksenbezems," 

 and "Hexsennestens," by the German names of "Hexen- 

 besen " and " Donnerbesen," by the French names of 

 " Balais de Sorcieres," and by the English names of 

 " witches' brooms " and " bird nests." They may be 

 caused by the insects Eriopliyes (Phytoptus] or by any 

 one of several species of fungi. 



A very severe and destructive witches' broom has 

 been reported from Surinam, British Guiana, Trinidad, 

 and Demerara. It causes the formation of bunches of 

 twigs which are very much enlarged and very knotty, 

 and often show strongly marked longitudinal furrows 

 at the base. The lateral branches are abundant, short, 

 and thick, and grow vertically. The leaves are usually 

 small, soft, and pliable. The flowers are numerous, in 



