INSECTS INJURIOUS TO MUSHROOMS. 7 
in St. Louis, Mo., reported that in one of his mushroom houses a bed 
150 feet in length had been completely destroyed by these pests, which 
attacked the mushrooms as fast as they appeared, honey-combing 
them and rendering them unfit for use. The method of attack 
of this insect 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 readily salable if 
the injury were not continued. When they 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 transformation, 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 control of springtails are 
to a large extent preventive, as these insects are somewhat difficult 
to control when once established in a mushroom bed. They are quite 
resistant to tobacco powders, but applications. of buhach or pyreth- 
rum to the beds are productive of some good. As they usually con- 
gregate near the surface of the beds fumigation with hydrocyanic- 
acid gas, according to the directions given in Circular 37 of this 
bureau, 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. 
By way of prevention, steaming all manure, as previously sug- 
gested for other species, will destroy springtails equally well. Where 
possible, it is better to grow the mushrooms at a temperature of about 
55° F. than higher, as at low temperatures the springtails breed 
much less quickly. Dusting the tops of the beds with powdered lime 
is also said to discourage attack by springtails. 
SOWBUGS. 
(Armadillidium spp. and Poreellio spp.) 
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, although 
known variously by the terms “ woodlice,” sowbugs, and “ pillbugs.” 
Two species, the greenhouse pillbug (Armadillidium vulgare Wa- 
