2 BULLETIN 127, U. S. DEPARTMENT OE AGRICULTURE. 



produced more than 30,000 pounds yielded less than 1,000 pounds of 

 mushrooms, owing to the ravages of this fungous disease. An 

 establishment containing over 50,000 square feet of mushroom beds 

 was abandoned on account of the heavy losses sustained. 



While the disease is prevalent in most localities where mushrooms 

 are cultivated on a large scale, there are mushroom-raising plants in 

 these infected districts where the disease has never made its appear- 

 ance. There is, however, evidence of a local distribution of the 

 disease, and unless proper measures to control the fungus are taken it 

 will be only a question of time before all mushroom houses are 

 infected. 



Costantin and Dufour (1892c) 1 state that under the ordinary condi- 

 tions of cultivation in a great number of the caves or underground 

 quarries in which mushrooms are cultivated abroad, the proportion 

 of diseased to normal mushrooms is about 1 to 10. In less frequent 

 cases this proportion rises to 1 to 4. Costantin and Dufour and 

 Repin (1897) report the losses to the Parisian mushroom growers 

 caused by this disease to be about $200,000 yearly. This loss is 

 based on a daily estimated production of about 56,000 pounds, at 66 

 cents per pound, the yearly production having a value of approxi- 

 mately $2,600,000 and losses due to the disease being estimated at 

 probably one-tenth of the production. As nearly as can be ascer- 

 tained these figures apply to the year 1892. 



OCCURRENCE OF THE DISEASE IN AMERICA. 



The occurrence of the fungous disease of cultivated mushrooms in 

 America was first called to the attention of the Department of Agri- 

 culture in 1909, when specimens of diseased mushrooms were sent to 

 the department with requests for a diagnosis of the trouble. A 

 microscopic examination revealed the presence of a fungus, a species 

 of Mycogone, similar to, if not identical with, the species causing the 

 European disease of mushrooms known as la mdle. 



HISTORICAL REVIEW OF THE MYCOGONE DISEASE. 



OCCURRENCE IN EUROPE. 



The Mycogone disease of cultivated mushrooms has been known in 

 England, France, and Germany for many years. In France it is 

 reported as having been recognized ' ' for at least three generations of 

 mushroom growers," and it is believed that it was known at a much 

 earlier date. Probably the first reference to the disease in scientific 

 literature was that of Magnus, who described it in 1888 as being the 

 most serious enemy of mushroom growing around Berlin. 



i All references to literature are indicated in the text by the name of the author and the year of publi- 

 cation. For full citations, see the list at the end of this bulletin. 



