318 GREENHOUSE MANAGEMENT. 



MUSHROOM ENEMIES AND DISEASES. 



The mushroom grower does not find it all smooth 

 sailing, as his crops are attacked by a number of insects 

 and other enemies, against many of which he has no 

 remedy except to give the houses a scrupulous cleaning 

 each summer. Little attention has been given to the 

 scientific study of the enemies of this crop, and many 

 may exist of which we have no knowledge. Most of the 

 pests of which we know injure the mushrooms by eat- 

 ing holes in, or biting off small pieces from, the tender 

 caps ; among these are the sow bugs or wood lice, slugs, 

 mice and other vermin. 



One of the most troublesome of these pests is the 

 mushroom maggot. It is about one-fourth of an inch 

 long, and is the larval form of a fly. It burrows through 

 the stems and caps of tender buttons, and in the full- 

 sized mushrooms the brown lines running through the 

 tissues are distinctly seen. The maggots appear in 

 April, and make it impossible to grow the ordinary 

 mushroom in the summer. It also attacks the new 

 mushroom (Agaricus rufescens), but from the rapid 

 growth of this species much less injury is done. If one 

 has a cave or cool cellar, they can be grown later in the 

 season than if the beds are in a warm place, but it is 

 even then about impossible to escape their attack be- 

 tween April and October. No remedy that is now known 

 will destroy them ; insect powder, kainit, salt and other 

 insecticides seem to have no effect upon them. 



The so-called "black spot" shows itself as black or 

 brown spots or streaks upon the top of the caps ; it is 

 also most troublesome during the summer months. The 

 diseased appearance is caused by minute eel worms which 

 enter the plants while they are quite small, and which 

 generally infect all in one clump. They are most 

 troublesome in old beds and seldom, if ever, appear in 

 properly made new ones. As soon as they are through 



