150 



BACTERIAL DISEASES OF PLANTS 



Inoculate by needle-pricks on the under surface of the fleshy 

 petiole, some petioles on one side only, some on both sides and 



Fig 



A, B. flagella of Bacterium campestre. Stained by van Ermengem's 

 silver nitrate method. X 1000. 



Fig. 89.- — A, Surface colonies of Bacterium campestre on nutrient agar. Plated 

 from D.C. rape. Time, 6 days. Photo Feb. 6, 1919. X 10. B, The same by 

 oblique transmitted light. 



in the middle, setting the needle deep enough to enter the bun- 

 dles. Other plants should be inoculated in the upper soft stem 



