Plants as Affected by Fungous Parasites. 173 



The affected part should be removed as soon as dis- 

 covered and burned at once, to destroy any spores of the 

 fungus it may contain or which might mature later. It 

 is generally important to cut the diseased branch some 

 distance below the point of visible infection, as in many 

 cases the mycelia of the fungus extend farther than 

 external appearances indicate. 



324. Preventing Spore Germination is the only known 

 method by which we can combat the fungi developing 

 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 germination 

 may be prevented by treating the seed with a solution of 

 certain chemicals or with hot water. Of the former, 

 sulfate of copper (copper sulfate, blue vitriol, bluestone) 

 has been most used, and unquestionably destroys the 

 spores of the smuts, but it has generally been found to 

 injure more or less the germination of the seed. 



325. The Hot-Water Treatment has proven fully as 

 successful in preventing smut as the preceding method, 

 without injuring the seed. This treatment consists in 

 immersing the seed for ten minutes in water at a tem- 

 perature of about 135 F. For treating a quantity of 

 seed, some special provisions are necessary, as it is some- 

 what difficult to bring every seed in contact with the 

 water at the proper temperature. Provide two large 

 vessels, as two kettles over a fire, or two boilers over a 

 cook stove one to contain* warm water (110-120 F. ), 

 the other to contain hot water (132-135 F.). Place a 

 reliable thermometer in the hot- water vessel that the 

 temperature may be watched. The warm water is used 



