DETAILED ACCOUNT OF SPECIFIC PLANT DISEASES 547 



a small opening. These ascospores bud off conidiospores, which are 

 capable of infecting the ovaries of rye plants, which have started their 

 growth toward maturity the following season. 



The ergot spurs are used medicinally under police regulations, for 

 they are dangerous and poisonous. In the Baltic provinces of Germany 

 and Russia, the peasant class frequently eat bread made out of flour in 

 which ergot spurs have been ground. They suffer from gangrenous 

 affections of the extremities with a loss of the hair, teeth and finger- 

 nails. A nervous form of ergotism has also been prevalent. Cattle 

 eating ergoted grain show similar gangrenous and nervous symptoms, 

 the loss of hoofs, tails and horns. 



Ergot can be controlled to some extent by the selection of the grain 

 seed and by removal of all ergoted masses, when detected in the 

 fields. 



A closely related species, Claviceps microcephala (Wallr.), TuL, was 

 submitted to the writer by the late Dr. Leonard Pearson on red-top 

 hay, which had been responsible for gangrenous affection of a herd of 

 cattle in Pennsylvania. 



Sweet Pea (Lathyrus odoratus, L.) 



Streak {Bacillus lathyri, Manns & Taubenhaus). — This disease had 

 been noted by the growers of the sweet pea in England, and recently, 

 it has been detected in the United States.^ Like the bacteriosis of 

 beans, streak makes its appearance in the season of heavy dew. On 

 the sweet pea, the disease usually appears just as the plants begin to 

 blossom; it is manifested by light reddish-brown to dark brown spots 

 and streaks (the older almost purple) along the stems, having their 

 origin near the ground, indicating distribution by spattering rain and 

 infection through the stomata. The disease becomes quickly dis- 

 tributed over the more mature stems until the cambium and deeper 

 tissues are destroyed in continuous areas, when the plant prematurely 

 dies. From the stems the disease spreads to the petiole, peduncles, 

 flowers and pods with symptoms similar to those on the stems. On the 

 leaves, however, the disease appears as small roundish spots, which 

 gradually coalesce, and eventually involve the entire leaf, which when 



^ Taxjbenhaus, J. J.: The Diseases of the Sweet Pea. Bull. 106. Delaware 

 Agricultural Experiment Station, Nov., 1914. 



