ERGOT FAMILY {Hypocreacece) 



ERGOT OF RYE {Svermoedia Clavus{D.C.]¥Yi^s.) 

 {Claviceps purpurea Tul.) 



Plate I. 



Common Names: Ergot of rye is generally known and spoken of as 

 ergot; but occasionally in European literature, reference is found to ''spur 

 kernels," ''blight kernels," and "spurred rye." 



Description: Ergot is a form of a fungus parasitic on grasses, one of 

 the best known species being that found on rye. The fungus is most 

 easily recognized in the second stage of its development, when the hard, 

 dark purple or almost black masses (sclerotia) are seen at intervals on the 

 heads of rye, where they have usurped the position of the seed of their 

 host. These sclerotia, or ergots, as they are popularly called, may be 

 observed from June till late in the autumn, according to the nature of the 

 species of ergot and host plant. In the autumn, they fall to the ground 

 and remain in a resting stage throughout the winter. When the warm 

 weather begins again, they show signs of awakening life by the appearance 

 of small cracks, through which diminutive stalked bodies (stromata) make 

 their way. In the head of the stroma are numerous flask-shaped cavities 

 (perithecia) each of which contains a number of narrow cells (asci) and 

 each of these in its turn contains eight thread-like spores or reproductive 

 bodies. The mature spores escape from the perithecia about the time of 

 flowering of the host plant, rye or grass, as the case may be. When a 

 spore falls into a floret of a suitable host plant, it develops a so-called 

 mycelium, and a honey-like substance called "honeydew" is abundantly 

 produced. The honeydew exudes in large glistening drops from the floret. 

 This sweet substance, which is eagerly sought by midges, flies and other 

 insects, is filled with very minute microscopic bodies (conidia), another 

 reproductive form of the fungus. The conidia are capable of immediate 

 germination and are carried by insects to other plants. Thus what is 

 known as "ergot disease" spreads rapidly throughout the flowering season 

 of its host. The mycelial threads continue to develop, and in time form 

 a dark compact mass two or three times the size of the seed of the host 

 plant. This new ergot eventually falls to the ground and the life cycle is 

 complete. 



Distribution and Host Plants : Dr. Staeger, of Berne, Switzerland, 

 has firmly established the fact that each species of ergot has its own circle 

 of hosts within which it moves exclusively. He has shown by successful 

 experiments carried on for a number of years past, that ergot of rye will 

 infect barley and the following grasses: 



Reed canary grass (Phalaris arundinacea L.) ; 

 Sweet vernal grass (Anthoxanthum odoratum L.) ; 

 Sweet or holy grass {Hierochloe odorata [L.] Wahlenb.) ; 

 Meadow foxtail (Alopecurus pratensis L.) ; 



