1923] 



LEHMAN — POD AND STEM BLIGHT OF SOYBEAN 



145 



from the other 3 strains in the presence of asci, numerous stylo- 

 spores, and less abundant production of pycnospores. By the 

 end of 17 days, all the strains had formed pycnospores on stems 

 of Melilotus alba, corn meal mush, and corn meal agar, and had 

 failed to sporulate on potato plugs and cooked rice, strain 17 

 forming stylospores in addition wherever pycnospores were 

 formed. By the end of 48 days, strain 17 had produced mature 



rnches of rainfall 



Fig. 8. 



perithecia on Melilotus alba stems, corn meal mush 



meal 



and cooked rice, while the other strains had 



failed to sporulate on the 2 last-named substrata 



As 



short a time as 41 days is sufficient for the production of mature 

 perithecia in cultures of strain 17 on soybean petiole. 



Relation of the Amount of Rainfall to Prevalence of 



Pod and Stem Blight 



Observations made during the summers of 1920, 1921, and 

 1922 indicate that the prevalence of, and the losses caused by, 



