168 DISEASES OF TROPICAL PLANTS 



CH. 



Nectria ditissima, Tull., which also attacks tea, etc. 

 (see page 46). 



Foot Disease. A foot disease, due to Euryachora 

 liberica, Oud., has been reported from Java. It attacks 

 the base of the tree, producing a stroma just beneath 

 the bark which eventually causes a splitting of the 

 bark. The diseased plants should be dug out and 

 burned, and new plants should not be set in the place 

 from which the old ones were dug. 



Root Diseases. There are, no doubt, a number of 

 root diseases, which are frequently referred to in the 

 literature, but which are very imperfectly understood. 

 However, it appears to the writer that many of these 

 diseases have their origin in the saprophytic fungi, 

 which develop on the decaying roots of other trees and 

 then spread to the coffee, on which they become parasitic. 

 At least one of these root parasites has been determined 

 as Irpexflavus, Klotsch, which is one of the Hydraceous 

 fungi. It has been reported from Malacca. 



Another of these root diseases is known as the leaf 

 blight, although it is quite different from that class of 

 diseases usually referred to as leaf blights. It is known 

 in Porto Rico, and is due to a fungus (Sclerotium) which 

 attacks the roots, causing a decay. It gradually 

 ascends the trunk, forming brownish or black mycelial 

 threads, and later a thick mass over the surface of the 

 leaves. The base of the leaf turns brown. 



Another root disease which has been reported from 

 Guatemala is due to a fungus which has been described 

 by D'Herelle as Phothora vastatrix. The mycelium 

 penetrates and clogs the sieve tubes, destroys the 

 cambium, spreads upwards, and finally causes the death 

 of the tree. The disease is at first detected by a 

 cracking of the bark near the ground. The exposed 

 wood is black and the disease at this time can usually 

 be traced three or four feet above the ground. The 

 disease may run for two years before the plant dies. 

 After the death of the plant, the perithecia can be found 

 beneath the dead bark. This disease also attacks trees 



