Mushroom Diseases 163 



The Mycogone Disease 



Caused by Mycogone pemiciosa Mag. 



The Mycogone is a very destructive mushroran 

 disease. The exact amount of its distribution in the 

 United States is as yet unknown. However, if 

 once introduced in a house, it is likely to ruin the en- 

 tire crop. 



Symptoms. The symptoms of the disease are 

 often various. The presence of the malady may be 

 indicated by small tubercules on the cap and by a 

 form of fluflFy white growth on the gills, which in- 

 terferes with their normal development. The result 

 is distorted caps and stipes, and finally, a general 

 darkening and decay of the tissue. In severe cases, 

 monstrous soft masses with thick white fungus coat- 

 ings are observed in houses in which the disease is 

 very prevalent. In this case, the afltected plants 

 have little resemblance to mushrooms. They decay 

 rapidly, and emit a very disagreeable odor. 



The Organism. The spores of Mycogone pemi- 

 ciosa are very characteristic. They consist of two 

 cells, the upper spherical, rough, and covered with 

 warts, the lower hyaline and smooth. Both cells 

 possess thick walls. 



Control. According to Veihmeyer,* there are no 

 evidences that tend to show that the Mycogone dis- 

 ease is carried with the spawn manufactured by the 

 "tissue culture" method. It is very probable, how- 

 ever, that the disease was introduced into this coun- 



•Veihmeyer, F. J, U. S. Dept of Agr. Bui. 127: 1-24, 1914. 



