THE MYCOGONE DISEASE OF MUSHROOMS AND ITS CONTROL. 21 



As the disease is carried by many different means, the greatest care 

 must be taken to prevent the infection of clean houses. There are, in 

 general, two ways in which infection may take place: (1) It may be 

 introduced into the house by means of the spawn and (2) the manure 

 or soil for the beds may contain spores of the fungus. In the first 

 case, the disease becomes evident as soon as the mushrooms begin to 

 make their appearance, and all portions of the beds are affected. In 

 the second case, beds may become inf ected by spores from a previously 

 diseased crop. Air currents free these spores from crevices or wher- 

 ever they may have lodged and thus assure a recurrence of the 

 trouble; insects may carry spores from other diseased beds, or from 

 diseased material which has been allowed to remain outsi'de the houses, 

 or spores may be carried on clothing or tools. When the spores of 

 the parasite are introduced in such a manner, the disease may make 

 its appearance a considerable time after the crop has begun to bear. 



The abandonment of diseased houses for less than three years will 

 be insufficient to rid them of the parasite, and a period of more than 

 three years may be necessary. 



Formaldehyde-gas fumigation and the observance of proper san- 

 itary measures should be employed. 



Formaldehyde gas, even in small quantities, retards the growth of 

 the fungus, and when sufficiently strong will destroy the spores. A 

 rate of 3 pints of formaldehyde or formalin per 1,000 cubic feet should 

 be used, in the proportion of 1 pint of formalin to one-half pound of 

 potassium permanganate. 



Fumigation will control the disease in the houses, but will not keep 

 them free, since bringing infected material, tools, etc., into the houses 

 will certainly start the disease anew; therefore every precaution 

 should be taken to prevent the reinfection of the houses after they 

 have been fumigated. 



Coal oil has no effect upon the spores of the parasite. 



Diseased material should be removed from the houses immediately 

 and treated with a disinfectant, preferably a solution of 1 gallon of 

 formalin to about 45 gallons of water. This disinfectant should be 

 used to spray all places where diseased material has been. Tools 

 and conveyances should also be treated. 



The disease is highly infectious, and the measures to be taken are 

 more prophylactic than palliative in their nature. 



Certain questions are yet to be solved concerning the life history 

 of the fungus, such as the^ development of a perfect stage, but the 

 method evolved for the control of the disease has proved effective 

 and has resulted in saving large sums to mushroom growers. 



