140 THE CHIEF SOUTHERN AGRICULTURAL CROPS 



annually causes very considerable losses. It is 

 usually the determining factor that necessitates the 

 plowing up and replanting of the old fields. For- 

 tunately vigorous, rapidly growing canes have great 

 powers of resistance to this disease and are very 

 seldom attacked. The intelligent use of fertilizers 

 and cultivation may be depended on as an absolute 

 specific for it. 



The rind disease Q3Ielanco7iium saccliari Wakker) 

 is everywhere present in cane fields. It is easily 

 recognized by the black horn-shaped masses of spores 

 that protrude from little pustules under the cortex 

 and conspicuously roughen and blacken the infected 

 areas. The fungus is normally a saprophite, living 

 on the dead cane tissues, and it cannot unaided 

 penetrate the epidermis of the health}^ cane. When- 

 ever this is wounded, however, by any cause, it is able 

 to gain an entrance, and it often causes great damage 

 in connection with or as a secondary effect from 

 some of the insects and diseases mentioned above. 

 This is particularly true of the leaf-hopper injuries in 

 Hawaii and the top-rot disease in Cuba. Canes 

 infested by the latter are quickly invaded by the 

 rind disease also. 



The dreaded Surah disease of Java has not yet 

 been found in America. The greatest care should 

 be observed in importing canes from the East for 

 experimental purposes lest this or other serious 

 pests be imported with them. This danger is well 

 illustrated by the case of the leaf hopper in Hawaii. 

 In fact it is so great that the transportation of cane 

 from one country to another should be strictly pro- 



