CANKER OF TOMATO: CULTURAL CHARACTERS 



213 



Cultural Characters. — Growth on thick vs. thin-sown agar 

 and gelatin plates. Behavior in agar and gelatin streaks and 

 stabs. Can you find two types of colony: a round, b spreading? 

 On which agar do you get the best results (a) +15, (6) +6, orj(c) 

 +0? Will the organism grow on —10 agar? — 20 agar? Appearance 

 on steamed potato; behavior in bouillon, and in nitrate bouillon; 



Fig. 156. — Stomatal infection on sprayed tomato leaf due to A plauohader 

 michiganense. The stoma is at A'. Under it the cells are destroyed and the 

 bacteria are abundant in the bundle. Time, 21 days. 



behavior in milk and litmus milk; streaks on htmus-lactose agar; 

 growth in peptone water in fermentation tubes with various sugars 

 and alcohols. Relative rapidity of growth in diluted tomato 

 and potato juices, as compared with Dunham's solution and pep- 

 tone bouillon (Titrate each to determine acidity and inoculate 

 sparingly with a 1-mm. loop from a fluid culture); behavior in 



