1923] 



LEHMAN — POD AND STEM BLIGHT OF SOYBEAN 133 



matic bodies on the blotting-paper. When transferred to sterile 

 soybean petioles, pycnidia and stromatic bodies characteristic 

 of Diaporthe Sojae were formed. Later stylospores were found 

 in one of these cultures. 



15. Made September 15, 1921. This isolation was made from 

 a plant with yellowing leaves and pods about half mature. 

 About 5 inches above the ground was a darkened stem segment 

 which was apparently infected. Hand sections revealed the 

 presence of mycelium in the tissues. The diseased segment was 

 placed in a moist chamber and pycnidia characteristic of D. 

 Sojae were formed in great numbers in the course of 5 days. 

 Pycnospores from these were spread on the surface of agar 

 plates and the colonies thus separated were transferred to sterile 

 soybean stems, where a production of mycelium and pycnidia t 

 typical of D. Sojae ensued. 



17. Made August 18, 1922. This isolation was made from 

 a pycnidium from a pod taken from the field on t he above date. 

 This is the only strain isolated which has formed stylospores 

 plentifully. It also produces perithecia in culture. When these 

 were first found, single ascus cultures were made for comparative 

 study and use in certain of the inoculation experiments described 

 below. 



18. Made August 18, 1922. This isolation was made at the 

 same time and in the same manner as No. 17, but from a pod 

 from a different plant. This strain has also formed perithecia 

 in culture. 



From the record of isolations given above, it is seen that 

 the fungus causing pod blight of soybean may be obtained in 

 pure culture from stems, pods, and seeds of diseased plants. That 

 the fungus resides within the seed-coat is beyond question, and 

 it seems highly probable that entrance was effected by actual 

 penetration of the unbroken testa before it had become dry and 

 indurated. Actual parasitism of the embryonic tissues is strongly 

 indicated by the details given for isolations of strains 6 and 7. 

 In the case of strain 6, the only alternative to this interpretation 

 is that hyphae may have grown between the cotyledons in such 

 a manner as to be beyond reach of the disinfectant. However, 

 the presence of discolored areas on the cotyledons is so strongly 



