18 



CIRCULAR 457, U. S. DEPT. OF AGRICULTURE 



hypopus can survive for a long time under adverse conditions. It 

 will grasp and cling to any moving object with which it comes into 

 contact, and is capable of being carried about by flies and gamasid 

 mites, and upon the clothing of workers in the mushroom houses. 

 Flies have been seen that were so covered with mites in the hypopial 

 stage that they were unable to fly. When the hypopus drops or is 

 brushed off, it continues its development into an adult mite if it 

 finds conditions favorable. 



Prevention of infestation by the mushroom mite is the only certain 

 means of avoiding damage to the crop. It is important that the 

 beds go through a good heat, as the mites are nearly always present 

 in the manure and can be controlled most effectively by killing them 

 at this time. Control by chemicals has been attempted, but in most 

 cases has not been successful, or only partially so. 



THE LONG-LEGGED MITE 



The long-legged mite (Linopodes antennaepes Banks) (fig. 7) is 

 less abundant than the mushroom mite. It is extremely difficult to 



contro 1. In some 

 places it occurs spo- 

 radically, while in 

 others, although near- 

 ly always present, it is 

 said to do little dam- 

 age. Since it is native 

 to this country, occur- 

 ring normally under 

 leaves and boards on 

 the ground out of 

 doors, it may be 

 brought into nearly 

 any mushroom house, 

 and if proper condi- 

 tions are present it 

 may develop into a se- 

 rious pest. The body 

 is very minute, yellow 

 to reddish brown in 

 color, and the legs, es- 

 pecially the front pair, 

 are very long and 

 slender. 



Very little is known 

 of the life history of 

 this mite. The mi- 

 nute round eggs are 

 laid in groups in the 

 casing soil and hatch 

 in about 8 or 10 days 

 into very small white 

 larvae. These molt in 

 6 or 8 days into nymphs, with longer front legs than the preceding 

 stage. These mites have never been observed damaging spawn, and 



Figure 7.- 



-The long-legged mite (Linopodes antennaepes). 

 X 70. 



