112 VEGETABLE PARASITES AND EPIPHYTES 



affected with strands or threads of sterile mycelium. 

 Microscopical examination of these threads by the Myco- 

 logist of the West Indian Department of Agriculture 

 showed that they are composed of parallel-running, 

 fungal hyphse closely woven together. When the hyphae 

 penetrate through the cortex to the deeper tissues of a 

 growth the latter is frequently destroyed. Leaves and 

 young buds may be kUled in a similar way. 



Thread blights are spread by the mycelium on dead 

 twigs and leaves which are carried by the wind to healthy 

 trees. 



A disease of a somewhat similar nature was observed 

 by Hart on cocoa trees in Trinidad. The threads closely 

 resemble a tuft of horse-hair caught in the twigs, and the 

 name " horse-hair " blight has been given to this disease. 

 In this case some of the threads were closely attached 

 to the bark from which hyphae were given off and pene- 

 trated to the deeper tissues of the branches. The fungus 

 responsible for this disease was determined at Kew as 

 Marasmius equicrimts, Mull. 



These diseases are not of a serious nature, and may be 

 readily checked by pruning off and burning the affected 

 portions of the trees. 



Similar diseases have been recorded in Ceylon, India, 

 and Java, where they affect tea and nutmeg, tea, and 

 coffee respectively. 



Fungus Diseases of Minor Importance. — Nectria Bainii, 

 Massee, is the name given by the Kew authorities to a 

 disease which attacks cocoa fruits in Trinidad. It 

 causes semicircular dark blotches to appear on the fruit- 

 walls, and the affected portions become soft and watery. 

 Eventually these become covered with a yeUow or orange- 

 coloured mycelium, from which small, red perithecia are 

 produced. 



At present the distribution of this pest is somewhat 

 restricted. Probably the methods suggested for the 

 control of " brown rot " of the fruits would be effective 

 in checking the spread of Nectria Bainii. 



Taphrina Bvssei, Faber, or " Balais de Sorciere," is said 

 to attack the branches of cocoa trees in Kamerun. The 

 remedy suggested is the cutting out and burning of affected 

 parts, in conjunction with the heavy pruning of the trees, 

 to facilitate the admittance of sun and air. 



