PLATE 32 

 Bacterium viridilividum, the cause of the Louisiana lettuce disease: 



A. — Three leaves of lettuce inoculated by needle pricks on February 15, 1915. 

 Photographed on February 17, 1915. The tissues are blackened, and decay is pro- 

 gressing rapidly. 



B. — Two pots of lettuce inoculated by spraying on February 19, 1915. Photo- 

 graphed on March 9, 1915. 



