xiii.] STRAW BLIGHT. 73 



is really a kind of larval condition of some more per- 

 fect fungus, the ultimate form of which has perhaps 

 never been seen, or, if seen, has not been recognised. 

 The nature of Oidium is described under the Oidium 

 of the turnip and under grass blight, Erysiphe graminis, 

 D.C. 



Grasses both wild and cultivated, living and dead, are 

 subject to the attacks of so many fungoid assailants that 

 it would be almost useless to guess at what the perfect 

 form of the fungus of grass blight might be. The 

 Graminecs and Cyperacece are unusually subject to the 

 attacks of fungi. Many of the pests are, however, super- 

 ficial, and do not possess the power of piercing and 

 traversing the cellular tissue. All, however, are ob- 

 jectionable, as they not only reduce the crop, but more 

 or less lessen its value as food. The phenomenon of 

 piercing the cells in the fungus of straw blight reminds 

 us of the corrosive mycelium of the fungi of the potato 

 disease found under Peronospora. Several species of 

 Fusisporium have been detected on cereals, but the 

 mycelia of these as seen by us do not well agree 

 with the spawn of straw blight. A fungus named 

 Fusisporium insidiosum, Berk., a parasite of the grass 

 named Agrostis pulchella, Kunth., is by no means well 

 known, and requires further attention. 



The loss to farmers from straw blight ranges from one- 

 half to one -fiftieth part of the crop, according to the 

 virulence of the attack ; but the blight is erratic in its 

 appearance, sometimes temporarily vanishing, and then 

 returning with great activity. Like some other mildews 

 and blights, but not all, straw blight is fostered by a 

 continuance of warm, wet weather. 



As the growth of straw blight is promoted by moisture, 

 it seems probable that if the quantity of water about our 

 cereal crops in wet seasons could be lessened by perfect 

 drainage, the amount of destruction from straw blight 

 would be less. Wheat and barley are not generally 



