PHYTOPHTHORA 129 



which, being dispersed by wind and rain, infects neighbour- 

 ing pods. The mycelium of the fungus permeates the 

 entire substance of the shell, and often also attacks the 

 seeds. Numerous resting-spores are produced in the diseased 

 tissues, and are liberated when the shell decays. These 

 resting-spores then germinate and produce the conidial form 

 of fruit, which commences the disease afresh another season. 

 This disease must not be confounded with the indurated 

 pods of cacao, caused by Colletotrichum lusificum (Hall and 

 Drost), which causes a black, hard patch on the shell, and is 

 common in Surinam and Demerara. Hyphae very slender, 

 irregularly branched, haustoria absent ; conidiophores slender, 

 simple, or sparingly branched, often nodulose at intervals 

 below the apex, corresponding to points that have borne 

 conidia; conidia lemon-shaped, 50-60X35-40 /x, liberat- 

 ing up to fifty zoospores on germination; oospores globose, 

 smooth, yellowish-brown, 24-30 fj. diam., often in clusters. 



Spray with dilute Bordeaux mixture when the pods are 

 quite young, and continue at intervals, depending on the 

 weather. 



Remove all diseased pods from the tree, and burn or bury 

 them, as the fruit never matures when attacked. 



The accumulations of old diseased shells, so commonly 

 met with in plantations, are a veritable hot-bed of disease, 

 and should be destroyed. 



The fungus attacks a large number of different kinds of 

 plants, more especially in the seedling stage. Seedling 

 cacao trees are often attacked. 



Low-lying, damp situations, and heavy shade favour the 

 disease. 



Massee, Keiv Bull. (1889). 



Black rot of betel-nut palm. Dr. Butler describes a 

 disease of the betel-nut palm (Areca catechu), prevalent in the 

 Malnad districts of Mysore. 



The first symptom appears at the time of flowering ; many 

 of the flowers fall without setting fruits, and the stalks 

 blacken and putrefy. The disease spreads along the inflor- 

 escence, and causes the nuts that are forming to drop at an 

 early stage. The injury gradually extends through the leaf- 

 sheaths until finally the growing-point in the centre of the 

 bud is reached, which is also destroyed, and the whole head 



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