4 INSECTS INJURIOUS TO MUSHROOMS. 
THE MUSHROOM MITE. 
(Tyroglyphus lintneri Osb.) 
The mushroom mite (T7yroglyphus lintnert Osb.) (fig. 3) is a 
minute, soft-bodied mite, smooth skinned, and white or whitish in 
color. It is closely allied to the common cheese mite (7yroglyphus 
siro I.) and resembles that species in appearance. It is, if anything, 
‘more prolific than the cheese mite, becoming at times so abundant 
in mushroom beds as to cover the surface of the compost, and when 
present in such numbers is extremely destructive, feeding upon the - 
mushrooms in all stages and penetrating the beds and destroying the 
mycelium. Indeed, in one case 
Vi observed by Mr. August Busck, 
y of this bureau,’ the mycelium 
was destroyed as fast as it grew 
from the spawn. 
This species is undoubtedly 
the cause in many cases of the 
failure of the spawn to grow, 
which is likely to be attributed 
to poor or weak spawn, or to 
defective cultural conditions. 
The minute size of the mites 
causes their presence to be little 
suspected, and the failure of 
the spawn to produce mycelium 
is not understood. Even under 
conditions favorable to the 
growth of the mycelium it is 
possible for the mites to increase 
to such an extent that the en- 
tire bed may be killed out. 
Besides the injury to the my- 
Wie. 3—-The iushroom mite (Tyrogiyphus Collum, mushroom: mites Valse 
neath Highly magnified. (From damage to the fruiting bodies 
Pe by eating into them, distorting 
or destroying the young growth. In the more mature mushrooms the 
mites may be found clustered in groups consisting of individuals of 
many sizes, usually hidden in the folds between the gills, where they 
burrow into the tissue and rapidly break down the caps. 
No direct observations bearing on the life history of this species 
have been made, but judging from that of related species it is about 
as follows: The eggs, which are large in proportion to the size of the 
mites, are laid in or about the mycelium of the mushroom, or on the 
1Bul. 38, Bur. Ent., U. S. Dept. Agr., p. 32, 1904. 
