MUSHROOM PESTS AND THEIR CONTROL 7 



tral alleyway. This gives slightly better distribution of gas and 

 also muzzles any flame that might otherwise be forced into the house. 



The fumes from the sulphur have not caused appreciable cor- 

 rosion of the galvanized metal, of which the greater part of the 

 burner is composed, during 2 years that it has been in use. The 

 iron frame has corroded to a slight extent, but the burner will prob- 

 ably last for a long time under ordinary conditions. 



The burner was designed to burn 32 pounds of flowers of sulphur, 

 this being the maximum dosage allowable in a standard mushroom 

 house of 16,000 cubic feet when at peak heat. With this dosage, 

 flame has at times been blown into the house through 10 feet or 

 more of pipe. When using the maximum dosage it has therefore 

 been thought best to cut down the speed of the fan by attaching 

 one or two electric-light bulbs to the line or by using a rheostat. In 

 empty houses excellent fumigations have been obtained with as lit- 

 tle as 20 pounds of flowers of sulphur. 



HEAT STERILIZATION 



In small spaces and where facilities are available, heat alone may 

 be used for the eradication of mushroom pests before the house is 

 filled. The source of the heat may be steam, or it may be electricity 

 if the current is very cheap. A temperature of 120° to 125° F., 

 if maintained for a few hours, should effectively rid the room of 

 all insect and mite pests. A 16-inch electric fan with the blades; 

 directed upward at an angle of 45° should be kept running during 

 this time to distribute the air evenly, otherwise the top of the space 

 will be very hot and the air for a few inches above the floor will 

 not be hot enough to kill the insects and mites. 



PEST CONTROL DURING PROCESS OF FILLING AND 

 HEATING OF BEDS 



When compost is placed in the beds a secondary fermentation 

 occurs and the temperature starts to rise. A small quantity of ma- 

 nure in a large cool place will not heat up so well as a greater quan- 

 tity, nor will it raise the temperature of the surrounding space 

 greatly. If the filling occupies too much time, considerable heat is 

 wasted. For this reason the house should be filled as quickly as 

 possible, the aisles swept out and cleaned of all loose manure, and 

 the doors closed tightly. Some growers fill a part of the house 

 and wait several days before filling the remainder. If manure is 

 scarce, it is better to form storage heaps until a sufficient quantity 

 is obtained to fill the house in one operation. 



NATURAL AND ARTIFICIAL HEATING 



It is most important that a good heat be obtained in the compost 

 at the time the house is filled because heat is the mushroom growers' 

 cheapest and best method of combating insects and other closely 



