



Annals 



of the 



Missouri Botanical Garden 



Vol. 10 APRIL, 1923 No. 2 



POD AND STEM BLIGHT OF SOYBEAN « 



SAMUEL G. LEHMAN 



Assistant Plant Pathologist, North Carolina Agricultural Experiment Station 

 Formerly Rufus J. Lackland Research Fellow in the Henry Shaw School 



of Botany of Washington University 



This disease was first called to the writer's attention in the 

 summer of 1920. During that season it occurred in abundance 

 on soybeans in the plant-breeding grounds of the North Carolina 

 Agricultural Experiment Station. Later it was briefly described 

 as Phoma blight of soybeans (Wolf and Lehman, '20). The 

 first observations were made about the middle of a somewhat 

 prolonged rainy season of that summer, and at that time com- 

 paratively few scattered plants of the early variety Black Eye- 

 brow had been attacked. From the relatively few plants which 

 first succumbed to its attack the disease spread rapidly, first 

 through the remaining plants of the above-named variety, and 

 later to some of the other varieties grown in these plats. Varieties 

 whose ripening processes in the main occurred after the rainy 

 season were lightly attacked. 



This disease is known to occur in North Carolina in the counties 

 of Wake, Pender, and Beaufort. It has been reported from no 

 other state, and no reference can be found in available pathologi- 

 cal literature to any soybean disease resembling the one de- 

 scribed in this paper. 



Observations made during 1920 and 1921, seasons very dis- 

 similar in respect to rainfall, indicate that the prevalence of, and 



1 An investigation carried out in part in the department of botany and plant 

 pathology of the North Carolina Experiment Station of the State College and State 

 Department of Agriculture, finished at the Missouri Botanical Garden in the 

 Graduate Laboratory of the Henry Shaw School of Botany of Washington Uni- 

 versity, and submitted as a thesis in partial fulfillment of the requirements for 

 the degree of doctor of philosophy. Published by permission of the Director of 

 the North Carolina Agricultural Experiment Station. 



Ann. Mo. Bot. Gard., Vol. 10, 1923 fm , \ 



