6 FARMERS^ BULLETIN 789. 



room maggots if taken in time, but tobacco fumigation may be 

 considered standard for this use. 



THE MUSHROOM MITE. 



The mushroom mite^ (fig. 3) is a minute, soft -bodied mite, smooth 

 skinned, and white or whitish in color. It is closely allied to the com- 

 mon cheese mite - and resembles that species in appearance. It is, if 



anything, more prolific, becom- 

 ing at times so abundant in mush- 

 room beds as to cover the surface 

 of the compost; when present in 

 such numbers it is extremely 

 destructive, feeding upon the 

 mushrooms in all stages and 

 penetrating the beds and destroy- 

 ing the mycelium.^ Indeed, in 

 one case observed, the mj^celium 

 was destroyed as fast as it was 

 produced. 



This species is undoubtedly the 

 cause in many cases of the fail- 

 ure of the spawn to propagate, 

 which is likely to be attributed 

 to poor or weak spawn or to de- 

 fective cultural conditions. The 

 minute size of the mites causes 

 their presence to be overlooked 

 and the failure of the spawn to 

 produce mycelium is not under- 

 stood. Even under conditions 

 favorable to the growth of the 

 mycelium it is possible for the mites to increase to such an extent 

 that the entire bed may be killed out. 



Besides the injury to the mycelium, mushroom mites cause damage 

 to the fruiting bodies by eating into them, distorting or destroying 

 the 3^oung grow^th. In the more mature nuishrooms the mites may be 

 found clustered in groups consisting of individuals of many sizes, 

 usually hidden in the folds between the gills, Avhere they burrow into 

 the tissue, causing the caps to break down. 



Fa;. 3. — Tlu> mushroom mite (TyroglypJn 

 Untncri). Highly magnified. (Banks.) 



■^Tyroijlyphux liritnrri Osb. 

 ^ TyroijliiphiiH siro L. 



3Tlie term mycelium, as used herein, is applied to the new growth of spawn through 

 the compost, as differentiated from the original insertions of spawn. 



