MUSHROOM PESTS AND HOW TO CONTROL THEM. 9 



feet in length had been completely destroyed by these pests, which 

 attacked the mushrooms as fast as they appeared, honeycombing them 

 and rendering them unfit for use. The method of attack of this in- 

 sect is to feed upon the fruiting bodies of the mushrooms, destroying 

 both the gills and the cap. Hundreds may be found clustered upon 

 a single mushroom and eating large cavities in the gills. It appears 

 to be a habit of these insects to congregate in large numbers on caps 

 which have been slightly injured, in which case they rapidly destroy 

 mushrooms which would be readih^ salable if the injury were not con- 

 tinued. When the}^ occur in large numbers they are likely to attack 

 even the perfect mushrooms, in aggravated cases destroying whole 

 beds. 



Insects of this group pass through no larval transfoi-mation, the 

 form of the newly hatched young being similar to that of the adult. 

 They are thus likely to be injurious in the same 

 manner throughout their life history. 



REMEDIES. 



The remedial measures applicable to the con- 

 trol of springtails are to a large extent preven- 

 tive, as these insects are somewhat difficult to 

 destroy when once established in a mushroom bed. 

 Springtails are quite resistant to tobacco ]:>owders, 

 but applications of " buhach " or pyrethrum in- fig. 4.— a common in- 

 sect powder to the beds are productive of some ^nlrJ^te'a^S^. 

 good. As they usually congregate near the sur- Much enlarged (Au- 

 face of the beds, fumigation with hydrocyanic- Choi's illustration.) 

 acid gas according to the directions given in Farmers' Bulletin 699 

 will prove effective in reducing their numbers. The cyanid should 

 be used at a strength of from 3 to 6 ounces to each 1,000 cubic feet 

 of air space, which will not prove injurious to the mycelium. The 

 fumigation should be applied after picking, as the gas "burns" the 

 caps severely, causing them to turn brown. 



By way of prevention, steaming all manure, as previously sug- 

 gested for other species, will destroy springtails. Where possible 

 it is better to grow the mushrooms at a temperature of about 55° 

 F. than higher, since at low temperatures the springtails breed more 

 slowly. Dusting the tops of the beds with powdered lime is also 

 said to discourage attack by springtails. 



SOWBUGS. 



Considerable injury is often accomplished to mushroom beds 

 through the attacks of oval, grayish or slate-colored creatures bear- 

 ing seven pairs of legs. These creatures are not true insects, 



