2 CIRCULAR 457, U. S. DEPT. OF AGRICULTURE 



This circular is designed to acquaint the grower with the principal 

 mite and insect pests of mushrooms, their life histories in a general 

 way, and the steps to be taken to prevent them from damaging the 

 crop. 



IMPORTANCE OF PROPER COMPOSTING FOR CONTROL 

 OF MUSHROOM PESTS 



Proper composting of manure for mushroom culture is an im- 

 portant factor in the control of mushroom pests. Composting is 

 best done upon a concrete floor. This prevents the entrance into 

 the manure of many pests from the ground and, if there is a gutter 

 around the edge that may be kept filled with water, many fly mag- 

 gots will be trapped and drowned therein as they leave the manure. 

 Whether composting upon concrete or upon the ground, the compost- 

 ing floor should be well scraped and cleaned, drenched with a solu- 

 tion of 1 gallon of formaldehyde to 50 gallons of water, and allowed 

 to air for from 2 to 4 days before the manure is placed upon it. 



Upon receipt, the manure should be well forked over, all lumps 

 and cakes broken up, and straw added if necessary. The tempera- 

 tures within the heap, except at ground level, are too high to allow 

 insects and mites to survive, but both mites and insects can develop 

 in the cooler outside layer of from 3 to 6 inches. The heap should 

 therefore be kept well ricked up during the composting so as to 

 expose as little surface as possible to attack. Along the ground level 

 the temperatures are often under 100° F., oxygen is practically lack- 

 ing, and the carbon dioxide concentration is very high. Under these 

 conditions the manure may remain uncomposted until it is turned 

 and thrown to the outside of the heap. This combination of low 

 oxygen and high carbon dioxide concentration, while perhaps caus- 

 ing pests to become inactive, probably kills very few of them and 

 does not prevent the entrance of others from the soil. 



One of the principal difficulties confronting the amateur who con- 

 templates growing mushrooms in small quantities in a cellar, barn, 

 or other structure is that of properly composting small quantities of 

 manure. This procedure is intimately related to the control of 

 mushroom pests. Severe infestations of flies, mites, and springtails 

 may result from the carriage of eggs and larvae into the beds with 

 the compost, unless the compost is in proper condition to go through 

 a good secondary fermentation or "heat" in the beds, to raise the 

 temperature to a point where insects and mites are killed. A half 

 ton of manure of average quality is sufficient for from 35 to 45 square 

 feet of mushroom bed, and it is extremely difficult to obtain proper 

 composting of less than this quantity. One of the advantages of 

 growing mushrooms upon a small scale is the practicability of screen- 

 ing the small compost heaps with cheesecloth to exclude insects; 

 another is the ease with which a small composting floor of concrete 

 or of 2- by 12-inch planks may be constructed, thus preventing the 

 entrance of insects from the soil. 



