128 DISEASES OF TROPICAL PLANTS 



CH. 



Still another rot has been reported from Cuba. It 

 attacks the fruit from the blossom end, frequently while 

 still on the trees. The cause is as yet undetermined. 



A splitting of the fruits, which is said to be due to 

 excessive moisture, has been reported from Italy. 



Brown Fruit Rot. This disease (Fig. 55), which is 

 due to a fungus, has been described by E. E. Smith as 

 Pythiacystis citrophthora, and is the cause of heavy 



FIG. 55. Lemon affected with brown fruit rot. (Photo by W. T. Home.) 



losses in California. It is especially severe on the 

 lemons, but also attacks other citrus fruits. It can be 

 found on the fruits in the orchards and packing houses, 

 but is most destructive on the fruit after packing. It 

 first appears as a brownish or purplish discoloration of 

 the rind, which is lighter on the green than on- the ripe 

 fruits, and is equally severe on weak and vigorous fruits. 

 It spreads rapidly from fruit to fruit, and is also 

 characterised by a peculiar odour, and by the presence 

 of small flies which are attracted to it. It is usually 

 followed by a growth of Penicillium. 



The disease is most abundant in the orchards during 

 wet weather, and on heavy soils. It can be controlled 



