1933] Proceedings of the Academy of Science 13 



a means of identiJScation of these closely related organisms. In the 

 case of two leafspot diseases of tobacco commonly designated as wild- 

 fire and angular leafspot caused by Bacterium tdbaccum and B. 

 angulatum respectively, both are able to form acid from dextrose and 

 saccharose but not from glycerine and lactose, but the farmer at- 

 tacks in addition mannitol and galactose whereas the latter is with- 

 out action on them. A similar specialization obtains in the case of 

 two leafspot organisms, Bacterium glycineum and B. sojae from soy- 

 bean. This study emphasizes the necessity of employing in phyto- 

 pathological studies the rare sugars for diagnostic purposes. 



Pod and Stem Blight of the Soybean. S. G. Lehman. (Kead by 



F. A. Wolf). 



This disease is capable of causing serious damage to the soybean, 

 particularly in wet seasons. It attacks pods, stems, and less fre- 

 quently, leaves, but greatest apparent loss results from attacks on 

 pods. Very yoving pods drop off when attacked, but older ones 

 remain firmly attached. The causal fungus penetrates the pod wall 

 and invades the developing seed. The ovule may abort at an early 

 stage, or, if attacked later in its development, the seed becomes 

 shriveled to various degrees depending on the time and severity of 

 infection. Seeds in diseased pods are often completely invested with 

 a conspicuous white fungus covering. Diseased areas on stems, pods, 

 and leaves become specked with minute black fruiting bodies, pycnidia, 

 which begin exuding small, hyaline, single celled spores within a 

 few days after their appearance. 



The causal fungus is placed in the form genus Phomopsis, and 

 in reference to its host, it is assigned the binomial ^'Phomopsis sojae." 

 It has been isolated from stems, pods, and seed, and has been ob- 

 served to cause the death of seedling soybean plants by growing from 

 the seed coat onto the hypocotyl and causing its decay. It over- 

 winters in diseased stems and seed. The practice of such sanitary 

 measures as plowing under diseased plants after harvest, use of 

 disease-free seed, and crop rotation are recommended as control 

 measures. 



Variation of Protein Content of Corn. H. B. Arbuckle and 0. J. 

 Thies. 



Appears in full in this issue. 



