32 MUSHEOOM GROWING AND SPAWN MAKING. 



yet the mushroom spawn grows slowly and continuously so long as 

 other conditions are maintained. From numerous experiments of 

 this nature it is apparent that the temperature relation is one Avhich 

 is governed by the competition to which the nmshroom spawn is sub- 

 ject in the bed. This is, of course, wholly in accord with the results 

 obtained from the study of the relative groAvth made by mushroom 

 spawn in fresh and composted manures. 



The statement previously made, therefore, that the optimum tem- 

 perature may vary slightly in different localities is true on account of 

 the fact that the mites, insects, and other animal pests of mushroom^ 

 growing may vary considerably in different localities, or under dif- 

 ferent conditions, even though there nuiy not be a great variation, 

 perhaps, in the bacterial and fungus flora of the compost uj^on 

 which the mushrooms are grown. Certain insects, for example, are 

 more abundant in a moist climate, but if special precautions can be 

 taken to eliminate all such pests, the growth problem is confined to 

 the interrelation existing between the nmshroom spawn and the 

 microscopic flora of the compost. ^lushrooms grown in the open 

 will probably show greater variation with reference to the tem- 

 perature factor than those grown in caves or cellars. 



AAliile a number of interesting problems would be presented by a 

 study of the interrelation of the mushroom mycelium with that of 

 other microscopic fungi i)resent in the compost, these are matters of 

 detail ; and it has been .Avholly impossible thus far to give any atten- 

 tion to suggestions which ha^-e been furnished by the experimental 

 data. It may be possible that other species of mushrooms are more 

 independent of insects and other microscopic fungi, and such fungi 

 may therefore be more suitable for cultivation at high temperatures 

 than is Agaricus campestn.s or any of its close allies. A considerable 

 effort is being made to obtain spawn of certain species of Agaricus, 

 and also of other edible mushrooms which make their appearance 

 during the warm weather. At this time, however, it is not possible 

 to say Avhat results of value may be anticipated from this line of 

 work. 



The direct effect of a temperature above the optimum upon the spo- 

 rophores is manifest through lengthening of the stipes and rai)id 

 expansion of the caps, ordinarily accompanied by toughness and 

 decreased size. In other words, the lower grade market product is 

 produced at the higher temperature. 



The moisture factor is also one of importance. It is undesiralile 

 that the place in which mushrooms are grown should be very damp, 

 or dripping with water. Nevertheless, a fairly moist condition of 

 the atmosphere should be maintaii^ed throughout the growing and 

 productive pei-iod. There should b.> grr.dual but slight eva])oration 

 from the surface of the beds, and sufficient ventilation to insure this 



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