MUSHROOM PESTS AXD THEIR CONTROL 



23 



having been found to succumb to 100.4° F. in one-half hour at a 

 relative humidity of 89 percent. If the temperature along the floor 

 does not reach this point, however, the mites in that location will 

 recover and reinfest the beds. They are very active and are capable 

 of crawling into cracks 

 in the floor and walls 

 to escape the heat. 



Since these mites are 

 found chiefly on or 

 near the surface of the 

 beds, the control meas- 

 ures recommended for 

 cecidomyiid fly larvae 

 should be effective 

 against them.. 



RELATED SPECIES 



In addition to the 

 above-mentioned mites 

 five other species are 

 occasionally found in 

 mushroom houses. 



Rhizoglyphus phyl- 

 loxerae Riley resem- 

 bles Tyroglyphus ex- 

 cept that it is larger, 

 with shorter body bris- 

 tles and darker legs. It 

 has similar habits and 

 life history, except that 

 the hypopial stage is 

 very common, so the 

 species is carried about 

 more readily by flies 

 and other insects. 

 This species is common 

 in compost heaps. A 

 good heat after the 



beds are filled, and prevention of the entrance of flies into the house will 

 do much to prevent an infestation. After they become established 

 the spawn is usually full of them, and little can be done except to keep 

 them from eating pits in the mushrooms themselves by close and 

 frequent picking of the infested mushrooms. 



Histiostoma sp., probably gracilipes Banks, is a, very small mite, 

 white, with a "warty" appearance. It feeds on both mushrooms and 

 spawn, and apparently carries bacteria which cause the death and 

 disintegration of mycelium and mushroom tissue. At any rate, 

 where these mites are found the spawn or mushroom has a brown, 

 watery, decayed appearance. Hypopi are produced in great numbers. 

 Prevention of entry and sanitation are the only known methods of 

 combating this mite. 



Tarsonemus confusus Ewing and T. floricolits C. and F. are 

 two very closely related forms of mites occurring sporadically, but 



Figure 9. 



-The long-legged mite (Linopodes anteyi- 

 naepes), X 70. 



