Plants as Affected by Fungous Parasites. 181 



324. Preventing Spore Germination is the only 

 known method by which we can combat the fungi de- 

 veloping within the host plant (endophytic (en-do- 

 phyt'-ic) fungi). 



In fungi that develop from spores planted with the 

 seed, as the smuts of the small grains, spore germina- 

 tion may be prevented by treating the seed with a solu- 

 tion of certain chemicals or with hot water. Of the 

 former, formalin is now most used, and unquestionably 

 destroys the spores of the smut, and while it has gen- 

 erally been found to injure more or less the germina- 

 tion of the seed, it is now recognized as the most effi- 

 cient and practical method of treating seed for the 

 prevention of smut in wheat, oats and barley. 



325. The Formalin (formaldehyd) Treatment con- 

 sists in immersing the seed in a solution of formalin 

 in water. To treat seed oats for the prevention of 

 smut prepare a solution of one pound (pint) of forty 

 per cent formaldehyd (formalin) in thirty-six gallons 

 of water. The seed should be submerged in this solu- 

 tion for ten minutes and then spread on a canvas or 

 floor to dry. 



For the treatment of barley seed for the prevention 

 of smut use one pint of formalin in twenty gallons of 

 water. 



326. Fungi that Develop from Spores Surviving 

 the Winter In or Upon the Soil, as the onion* smut, 

 cannot be prevented by disinfecting the seed. For this 

 disease a mixture of flowers of sulfur and air-slaked 



irocystis Cepulce. 



