PLATE 35 



A. — Louisiana lettuce disease: Surface colonies on agar-poiu-ed plates of Bacterium 

 -jiridilividum, showing the mottled type of colonies, and also one buried colony. 

 Photographed at the end of six days. X9. 



B. — Bad. viridilividum: Nonmottled type tliree days after pouring. Both types of 

 colonies are infectious. X9. 



C. — Bact. vitians, cause of the South Carolina lettuce disease: Agar-poured plate 

 showing surface, btiried, and bottom colonies. Photographed at end of the third 

 day. Xg- 



D. — Bact. viridilividum, cause of a Virginia lettuce disease: Mottled colonies on 

 agar-poured plates. Photographed two days after pouring. Tlie streak is a pencil 

 mark on the outside of the dish. X5- 



E. — Bact. marginale, cause of the Kansas lettuce disease: Colonies on surface of 

 agar-poured plates. Photographed three days after pouring. Xio. 



