THE MONTHLY BULLETIN. 



281 



the surface a flabby appearance. These markings may be distributed irregularly 

 over the surface of the affected parts or, as is often seen, occur in half circles or in 

 lines. 



The disease was first noticed in Florida about IN'.rj by W. T. Swingle and II. G. 

 Webber, and described by them in ls'.lii. In 1912 the causal agent was shown to be 

 Phomopais Ottri, the same fungus that the writer had previously described as the 

 cause of stem-end rot of citrus fruits in Florida. It appears to be the most severe 

 in certain portions of Florida, although it is known to occur in Louisiana and oilier 

 Golf states in a mild form. As far as known it does not occur in Cuba, which is 

 an important citrus section, nor has it ever been found in California. 



Fig. SG. Melanose (.Phomopais citri) on the skin of grapefruit. 

 Cal. Agr. Exp. Station.) 



(Bui. 262, 



This disease occurs on all varieties of citrus fruits in Florida, but it is perhaps 

 most noticeable on grapefruits, because of the smoothness of the skin of that fruit. 

 Melanose starts on leaves and shoots only when there is a flush of growth. On the 

 fruit it may start at any time from just after the petals fall until late summer or 

 early fall. 



The fungus causing Melanose and stem-end rot lives most naturally in dead 

 branches, and even in very small twigs, where in moist weather it produces countless 

 numbers of minute spores. These spores are produced in small bodies in the bark 

 that to the unaided eye look like dark specks or minute raised pustules on the surface 

 of the dead bark. The fungus is probably spread in the tree chiefly by dew and rain. 

 The spores are washed down from the dead twigs to the fruit, leaves and new grow- 

 ing twigs. Birds and insects are also, no doubt, instrumental in carrying the spores 

 from tree to tree. Pruning out dead twigs and branches and spraying are the means 

 used in Florida to control this disease. 



