At the lower temperature there was little or no evident appearance 

 of other fungi, molds, or insects; 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 which is governed by the competition 

 to which the mushroom spawn is subject in the bed. This is, of 

 course, wholly in accord with the results obtained from the study 

 -of the "relative growth made by mushroom spawn in fresh and 

 composted manure. 



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 mush- 

 room growing may vary considerably in different localities, or un- 

 der different conditions, even though there may not be a great varia- 

 tion, perhaps, in the bacterial and fungus flora of the compost upon 

 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 mushroom spawn 

 and the microscopic flora of the compost. Mushrooms grown in 

 the open will probably show greater variation with reference to 

 the temperature factor than those grown in caves or cellars. 



The direct effect of a temperature above the optimum upon the 

 aporophores is manifest through lengthening of the stipes and rapid 

 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 undesirable 

 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 maintained throughout the growing and 

 productive period. There should be a gradual but slight evapora- 

 tion from the surface of the beds and sufficient ventilation to insure 

 this, is believed to be essential. It is certain that in poorly venti- 

 lated caves mushrooms do not succeed. On the other hand, in a 

 dry atmosphere, or exposed to drying winds, mushroom beds soon 

 cease to bear, while such sporophores as are developing may have 

 their caps cracked or torn. 



