MUSHROOMS 419 



pests are sometimes responsible for total crop failures. 



Small flies or gnats of various descriptions are among 

 the most common pests. They are invariably present in 

 untreated manure, and under favorable conditions mul- 

 tiply very rapidly and soon become a great nuisance. 

 High temperatures are especially favorable for the breed- 

 ing of these pests, and therefore they are most likely to 

 damage mushrooms in beds which have been spawned 

 early in the autumn or before the advent of cold weather, 

 for the flies are practically inactive at temperatures below 

 55 degrees. The damage is caused by the larvae of mag- 

 gots passing up through the stipes and riddling the caps. 

 Fumigation with tobacco (page 105) at the strength gener- 

 ally employed in greenhouses will kill the adult flies. 

 Hydrocyanic gas (page 109) may be employed before the 

 beds are spawned. Bulletin 155, U. S. Bureau of Ento- 

 mology, gives a description and life history of the various 

 insects which feed on mushrooms. 



The mushroom mite (Tyroglyphus linteri) is always 

 present in stable manure, and it may cause serious dam- 

 age to the crop if the manure has not been properly 

 composted. It multiplies most rapidly at high tempera- 

 tures and in dry manure ; this is an important reason for 

 maintaining an adequate supply of moisture in the com- 

 post pile. Apparently there is no practical means of 

 eradicating the pests when they appear after the beds 

 have been spawned. They feed both upon the spawns 

 and upon the mushrooms. 



Springtails are very minute, grayish-black insects, 

 which sometimes appear in great numbers upon the sur- 

 face of the beds. These pests are most likely to be 

 troublesome in damp, poorly ventilated houses or caves. 

 They generally attack the mushrooms through the gills. 

 Thorough ventilation, applications of pyrethrum powder, 

 and the dusting of the beds and floors with quicklime are 

 among the remedies recommended. 



