Farmers' Bulletin 789 



be thoroughly scalded, and the ■wood- 

 work of the mushroom house treated 

 to a wash of creosote or crude car- 

 bolic acid, either of which is repellent 

 to the mites. After complete disinfec- 

 tion has been accomplished the house 

 should be screened, to guard against 

 subsequent introduction of the pest by 

 means of flies. Care should be used 

 to purchase spawn coming from re- 

 liable sources. With these precautions 

 it is unlikely that trouble will be ex- 

 perienced from the attacks of mush- 

 room mites. Close watch should be 

 kept, however, for any signs of their 

 presence in the beds, and the compost 

 destroyed upon their first abundant 

 appearance, as it is impossible to ob- 

 tain good results with mushrooms 

 when they are once thoroughly in- 

 fested by these mites. All applica- 

 tions of sufficient strength to destroy 

 the mites are likewise injurious to the 

 mushrooms, and it is futile to attempt 

 to control them by any artificial means 

 once the mushroom bed has become 

 Infested, as the mites are buried so 

 deeply in the compost that no insecti- 

 cide will reach them. 



Fig. 3. — A common injurious springtail, 

 Achoreutes armatum. Much enlarged 



A predacious mite, which belongs to 

 another family," frequently occurs in 

 beds infested by the mushroom mite, 

 feeding upon the latter, and at times 

 becoming so numerous as entirely to 

 wipe out the pest. This predacious 

 mite may be known by its reddish or 

 brownish color, its longer legs, and its 

 manner of running swiftly over the 

 compost or the mushrooms. Cases 

 have been observed where it has oc- 

 curred in such abundance as greatl.v 

 to outnumber its host. It does not 

 attack the mushrooms after the de- 

 struction of the mushroom mite, but 

 seeks other feeding grounds or dies of 

 starvation. 



SPRINGTAILS 



At times the surface of a mushroom 

 bed becomes alive with minute brown 



or black insects which, when dis- 

 turbed, leap about like fleas in an ex- 

 tremely erratic manner. These are 

 known as springtails,' since the spring- 

 ing is performed by the aid of two 

 short bristles situated on the end seg- 

 ment of the abdomen. These insects 

 (see fig. 3) are often attracted to the 

 manure used as compost, where they 

 feed on the decaying vegetable matter 

 present, but on occasion they may be- 

 come very injurious in mushroom 

 houses. A correspondent in St. Louis, 

 Mo., reported that in one of his mush- 

 room houses a bed 150 feet in length 

 had been completely destroyed by 

 these pests, which attacked the mush- 

 rooms as fast as they appeared, honey- 

 combing them and rendering them un- 

 fit 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 perfect mushrooms, in ag- 

 gravated cases destroying whole beds. 

 Insects of this group pass thfough 

 no larval transformation, the form of 

 the newly hatched young being simi- 

 lar 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 de- 

 stroy when once established in a 

 mushroom bed. Springtails are quite 

 resistant to tobacco powders, but ap- 

 plications of " buhach " or pyrethrum 

 insect powder to the beds are produc- 

 tive of some good. As they usually 

 congregate near the surface of the 

 beds, fumigation with hydrocyanic- 

 acid gas, as for the mushroom fly 

 (p. 2), will prove effective in reduc- 

 ing their numbers and will not prove 

 injurious to the mycelium. The 

 fumigation should be applied after 

 picking, as an excessive strength of 

 the gas is likely to " burn " the caps 

 severely, causing them to turn brdwn. 



Ky way of prevention, it is lietter. 

 where possible, to grow the mush- 

 rooms at a temperature of about 55° 



' Gamasidao. 



Achoreutes artiiatiim Nicolet et al. 



