133 MUSHROOMS, HOW TO GROW THEM. 



will cause fogging off to overtake every little mushroom 

 that had been attached to these mycelium threads. 

 Keeping the bed or part of it continuously wet or dry 

 will cause fogging off, so will drip ; watering with very 

 cold water is also said to cause it, but this I have not 

 founi to be the case. Unfastening the ground by ab- 

 ruptly pulling up the large mushrooms will destroy 

 many of the small mushrooms and pinheads attached to 

 the same clamp ; and when large mushrooms push up 

 through the soil and displace some of the earth, all the 

 small mushrooms so displaced will probably waste away, 

 as the threads of mycelium to which they were attached 

 for support have been severed. A common reason of 

 fogging off is caused by cutting off the mushrooms in 

 gathering them and leaving the stumps in the ground ; 

 in a few days' time these stumps develop a white fluff 

 or flecky substance, which seems to poison every thread 

 of mycelium leading to it, and all the mushrooms, pres- 

 ent and to come, -that are attached to this arrested web 

 of mycelium are affected by the poison of the decaying 

 old mushroom stump, and fogg off. Any impure matter 

 in the bed with which the mycelium comes in con- 

 tact will destroy the spawn and fogg off the young 

 mushrooms. Lachaume complains about the larvae of 

 two beetles, namely Aphodius fimetarius and Dermestes 

 tessellatus, which " cause great damage by eating the 

 spawn, thereby breaking up the reproductive filaments." 

 Damage of this sort by these or any other insect vermin 

 will cause fogging off. But I have not noticed either of 

 the above beetles or their larvsB about our beds. 



Flock. — This is the worst of all mushroom diseases 

 and common wherever mushrooms are grown artificially. 

 It is not a new di sease ; I have known it for twenty-five 

 years, and it was as common then as it is now, and prac- 

 tical gardeners have always called it Flock. I say 

 "worst of all diseases" because l know that mushrooms 



