MUSHROOM ENEMIES 



mushroom production, or even the growth 

 of spawn. It is one of the undoubted 

 sources of failure when the conditions are 

 unfavorable. Just as in the case of the 

 gnat, the mite is less active at the lower fa- 

 vorable temperatures and unless it has be- 

 come exceptionally abundant before the beds 

 are made, it will not be an important factor 

 with the growth conditions satisfactory. 

 The writer has tried many types of fumiga- 

 tion in an endeavor to eliminate this insect 

 from the manure, but has failed to find any 

 practical means whereby it may be killed. 

 Fumigation with the deadly hydrocyanic 

 acid fumes four times the strength usually 

 employed has served to kill the majority, 

 but a sufficient number survived this treat- 

 ment to make it seem scarcely worth while. 

 It would, of course, be possible to kill all 

 insects as well as fungi by steam sterilization 

 of the manure, but for a variety of reasons 

 I am unable to hold out the hope that this 

 operation will simplify the problems as a 

 whole. The best that can be said is that 



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