Plate VII. — Sweet potato diseases, a, Sweet potato show- 

 ine the characteristic shriveling produced by the root-rot fun- 

 oTis. 6, A sweet potato showing discoloration caused by the 

 scurf fungus, c and d, Showing ring-rot, frequently found in 

 storage-houses, e, Java black-rot. A sweet potato showing 

 the drv mummied condition produced by the fungus. Note the 

 numerous pimple-like protuberances containing spores borne on 

 the surface. /, Foot-rot. g, Dry-rot. h, Black-rot. A sweet 

 potato showing the black circular spot caused by black-rot 

 fungus. 



