SOME MUSHROOM DISEASES AND THEIR CARRIERS 6 



answer the same purpose. These are very small bodies called spores, 

 thousands in number, each capable of starting a new plant and caus- 

 ing the disease. Mycogone or the bubbles fungus is doubly danger- 

 ous because it has two kinds of spores. One kind, which develops 

 early, is produced on the cottony growth on the mushrooms. These 

 spores are very thin walled and can not endure unfavorable condi- 

 tions of temperature, humidity, or fumigation. The second kind of 

 spore is two celled and thick walled, which makes it more resistant 

 to unfavorable conditions such as heat and cold. The fungus in this 

 stage is more difficult to destroy; consequently, it is important to 

 collect and burn all diseased mushrooms as soon as they are ob- 

 served, that is, when they show the velvety coat and before they have 

 become soft and brown or smell bad. 



In addition to spores, the fungus has a vegetative part, the my- 

 celium, corresponding to spawn and consisting of a threadlike growth 

 (hyphae) which works its way into the cracks or crevices of the wood 

 of the beds and unless the houses are fumigated thoroughly will live 

 over and start the disease again the next year. 



CONTROL MEASURES 



Two lines of attack — sanitation and fumigation — are absolutely 

 essential in order to control the disease. 



SANITATION 



Sanitation is of primary importance, and without it fumigation is 

 only half effective. As soon as a mushroom shows the bubbles dis- 

 ease it should be removed and burned. The practice of putting 

 diseased mushrooms just outside the entrance to a mushroom house is 

 of greatest danger, for the following reasons: (1) There are always 

 air currents or wind which carry the spores into the houses; and (2) 

 insects, especially flies, also carry spores. As shown by microscopic 

 examination, the spores of the fungus cling to the wings, feet, and 

 other parts of the body of the flies, and in this manner the disease is 

 easily carried from an infected house to a healthy house, even to 

 considerable distances. Another very easy way by which the dis- 

 ease is distributed is by mushroom pickers or other workmen who go 

 from house to house attending to watering, ventilating, or other 

 work. Soil containing spores of the fungus readily clings to tools, 

 shoes, hands, or even clothing ; therefore persons working in infected 

 houses should not be permitted to go to a healthy house, or at least 

 not before changing clothing or taking other precautions to prevent 

 carrying spores from diseased mushrooms. 



Where the method of ventilation includes opening the entire house, 

 the danger from insect carriers of disease becomes very great. The 

 screening of ventilator shafts and doors will materially lessen this 

 source of infection. 



The disposal of material from old beds is a very difficult matter, 

 especially when mushroom establishments are near together. The 

 manure from the beds is still of value as fertilizer and is easily dis- 

 posed of to truck growers, but its utilization on near-by farms is 

 one of the surest means of reinfection and spread of the disease. 

 Some growers dispose of their manure very advantageously to golf 



