308 



DISEASES OF ECONOMIC PLANTS 



The wilting of the fohage and the blackening of the bun- 

 dles are distinctively characteristic' 



A soil bearing diseased plants one season is subject to 

 the malady in succeechng years and must be abandoned 

 for tomato culture. The disease is spread from plant to 

 plant largely by the potato bug (Colorado beetle) and other 



Fig. 134. — Tomato field showing effect of wilt (bacillose). Original. 



insects. For this reason all leaf-infecting insects should be 

 given special attention. Otherwise this disease in symp- 

 toms, cause, dissemination, and treatment is similar to the 

 usual soil diseases. 



Wilt, fusariose {Fusarium sp.). — A form of fusariose has 

 been described in California by Smith ^ as follows : It 

 occurs not infrequently as the cause of losses up to 100 



> Smith, E. F., U.S. Dept. Agr. Div. Veg. Phys. & Path. Bui. 12, De- 

 cember 19, 1896. 



2 Smith, R. E., Cal. Agr. Exp. Sta. Bui. 175, January, 1906. 



