INSECTS OF THE GREENHOUSE. 319 



bearing, the old beds should be thrown out, and new 

 ones made entirely from fresh materials. If the worms 

 have been present, the walls and floor should be thor- 

 oughly whitewashed, and all decaying matter and dis- 

 eased mushrooms should be removed at orce. By the 

 free use of lime and salt, the green mold in which they 

 multiply can be kept down. Boiling water is also 

 recommended for this purpose, to be applied to the 

 walls, floors, boards, and sparingly to the surface of the 

 beds, before the mushrooms appear. 



One of the most common and troublesome diseases 

 of the mushroom is known as "fogging off." It, how- 

 ever, seems to be a secondary trouble, as it as a rule only 

 attacks mushrooms that have been injured in some way. 

 If the bed is too wet, or too dry, or if the surface is dis- 

 turbed in such a way as to loosen the young mushrooms, 

 they will fog off, so that the disease seems to partake of 

 a fungous as well as of a bacterial nature. 



The so-called "flock" is even more to be dreaded. 

 It is caused by one or more fungi that attack the gills of 

 the mushrooms. They become thick and hard, and are 

 often distorted. The conditions that favor the devel- 

 opment of the disease are not understood and the only 

 known treatment is to destroy the spawn upon which a 

 diseased mushroom appears. 



In growing mushrooms, much can be done to ward 

 off the attacks of these various diseases and insects by 

 keeping the house clean and free from litter and rubbish ; 

 the beds should be removed as soon as through bearing, 

 and in the new beds only fresh material should be used. 



tlf the atmosphere is too dry, mushrooms are some- 

 times injured by a species of mite, closely related to the 

 "red spider," but as they are only troublesome under 

 the above conditions, the way to prevent their appear- 

 ance and of freeing the beds of their presence will be at 

 once apparent. 



