The ..Silverthread" Disease of Coffee in Surinam 



by 



J. K U IJ P E R. 



(With Plate VII and VIII.) 



Introduction. 



The Sarinam coffee {Coffea arabica) as well as Liberian 

 Coffee {C. Uherica) is attacked by a disease, which mani- 

 fests itself by the hanging of one or more dead leaves 

 on the top of the branches. Thèse leaves are attached to 

 the branch by a thread, which is formed by a great 

 number of twisted hyphae; on further examination the 

 branch shows, besides the leaves hanging from it, which 

 are quite withered, some leaves with smaller or larger 

 brown spots. On the underside of thèse leaves a cobweb- 

 like tissue of h^'-phae is found, which in dry weather on 

 leaves, not yet badly attacked, has a silvery white ap- 

 pearance, hence the name ,,silverthread" (Dutch : zilverdraad) 

 has been given to the disease. 



Usually bundles of hyphae spread ont on both sides of 

 the midrib; as they proceed further up the leaf they 

 gradually spread as a délicate web over the whole leaf 

 surface. In the other direction one can follow the strand 

 along the branch, often even far down the mainstem of 

 the tree. 



I noticed the disease on ail the estâtes which I visited. 



Diseases such as this hâve been described by several 



