34 



One thing was ascertained through these experiments, namely, that 

 the mushroom mycelium is not injured by the treatment with vapors 

 of bisulphid of carbon; in fact, the growth seemed rather stimulated 

 if affected at all, and such beds, when not ultimately killed by the 

 mites, produced as good a crop as those not treated. The fruit bodies 

 above ground, however, can not stand the treatment, but disinte- 

 grate very soon, for which reason all should be plucked before the 

 application. 



(B) Pulverized sulphur was applied liberally with a blower, and 

 mixed with about 1 inch of the top soil by means of a rake. Aside 

 from such mites as were injured in the handling, and such as were 

 actually buried in the sulphur, from which they had difficulty in extri- 

 cating themselves, none seemed in the least affected. 



(C) Vapors of sulphur. — The burning of chips of sulphur in proper 

 receptacles on top of the beds did not have any apparent effect on the 

 mites. 



(D) Pyretlwum, powder applied liberal^ with bellows had no serious 

 effect on the mites, though they evidently did not like it. It did not 

 seem to act even as a deterrent in such beds as were little or not at all 

 infested. However, the undoubted beneficial results against roaches 

 and flies, which might otherwise have become serious factors, would 

 warrant the use of this insecticide freely in all mushroom beds as a 

 good precaution. 



(E) Hydrocyanic-acid gas. — Conditions did not allow a thorough test 

 of this, but 1 have no doubt, from what was done, that it is as ineffect- 

 ive against the mites as bisulphid of carbon. One large bed in a 

 cellar by itself was left from Saturday -i o'clock to Sunday 4 o'clock, 

 exposed to the fumes of hydrocyanic acid, produced in the usual way. 

 When the windows were pulled open on Sunday strong fumes were 

 still found. 



No living mites were noticed at the inspection on top of the bed, 

 but digging into the bed the following day revealed them apparently 

 as well as ever. Concerning the influence of these vapors on the 

 growing mycelium this experiment gave no information, as the 

 mycelium in this bed was already dead when exposed to the gas. 



(F) Tobacco dust was tried in a single bed, and gave the same nega- 

 tive result as sulphur, acting at most only as somewhat deterring but 

 not killing the mites. 



(G) Chloride of lime and gasoline. — Neither was given sufficient 

 trial to warrant final conclusions. The former killed the mites which 

 came in contact with it, but two beds on which it was applied did not 

 produce any mushrooms either. The gasoline did not seem to have 

 any fatal results either to mites or mushrooms. 



(H) Moisture. — A mushroom bed does not allow much variation in 

 moisture if good results are to come. However, it was soon observed 



