164 



BACTERIAL DISEASES OF PLANTS 



organisms. The bases may now be removed, crushed in a sterile 

 mortar and allowed to soak in bouillon for some hours before 

 plates are poured. Some of the latter should be sown heavily. 

 Keep the tubes and pour a second set of plates next day; pour 



Fig. 104. Fig. 105. 



Fig. 104. — Corn plant showing very pronounced dwarfing, premature develop- 

 ment of male inflorescence and stooling due to Aplanobacter stewarti. Vessels 

 full of the yellow slime. From Chula Vista, California, in 1915. 



Fig. 105. — Spots on inner husk of a sweet-corn ear as a result of bacterial cavi- 

 ties due to Aplanobacter stewarti. Plant from infected seed. Spots bright 

 yellow. 



also from dilutions of the same, if clouding has developed. There 

 are various non-parasitic, motile, yellow schizomycetes on the 

 surface of corn kernels, and only those non-motile forms which 

 behave properly in the agar, gelatin, nitrate bouillon, litmus 



