Family Legurainosas 263 



phur, or by spraying with potassium sulphide at the 

 rate of three ounces of the chemical dissolved in ten 

 gallons of water. 



SCLEROTINIA ROT 



Caused by Sclerotinia libertiana Pcki. 



Sderotinia rot is a disease which attacks fall snap 

 beans. The trouble is prevalent in Norfolk, Virginia, 

 where it has been studied by McClintock. ' During 

 a period of hot himiid weather in September the 

 disease may suddenly break out in great severity. 

 Usually withering and decaying of stems and pods 

 where the plants are thickest is the first sjmiptom that 

 attracts attention (fig. 51 c). On closely examining 

 infected stems and pods, we find that they are water- 

 soaked, and overrun by the white mycelial growth 

 on which appear numerous hard, black sclerotia. In 

 the field, the Black Valentine snap bean seems to be 

 more resistant to rot. For a description of the 

 causative fimgus and methods of control, see lettuce 

 drop, p. 143. 



Anthracnose 



Caused by Colletotrichum Undemuthianum (Sacc. 

 & Magn.) B. and C. 



Anthracnose may be considered one of the most 

 destructive bean diseases. However the trouble 



' McClintock, J. A., Phytopath. 6 : 436-441, 19 16. 



