MUSHROOM PESTS AND THEIR CONTROL 



17 



enough the flies will not be attracted in great numbers, and if it is 

 too intense they seem to be satisfied before they actually reach the 

 trap and do not come any nearer to it. 



A very simple and easily constructed light-suction trap of this 

 type is shown in figure 5. The frame, shown in figure 6, is con- 

 structed of y 2 -mch strap iron, bent cold in an ordinary machinist's 

 vise. All bolts used are 

 % 6 -inch stove bolts with the 

 exception of the two that 

 hold the motor ring to the 

 rest of the frame, which are 

 %6 _mcn flat-headed bolts. 

 The barrel is a 5-quart oil- 

 can, such as can be obtained 

 at any service station, with 

 both ends removed. The 

 fan motor should be adapted 

 to operation in a vertical 

 position, and should be fully 

 enclosed to prevent the clog- 

 ging of the armature with 

 dead flies. A motor of this 

 type, with the fan, costs 

 about $7. 



The trap can be con- 

 structed in about 30 min- 

 utes with the tools usually 

 found about a home or farm 

 workshop, at a total cost, 

 with the exception of the 

 motor, of around 35 cents. 



In operation the trap is 

 hung up by its wire loop, 

 and a bag of light cheese- 

 cloth is tied to the bottom 

 of the barrel with cord, the 

 flange of the cap crimp pre- 

 venting the cord from slip- 

 ping off. 



Figure 6. 



-Details of frame of light-suction 

 trap. 



INSECmciDAL DUSTS 



There are a number of insecticidal dust mixtures on the market 

 that are used for mushroom fly control. A dust composed of 60 

 percent of pyrethrum, with 40 percent of finely ground diatomaceous 

 earth or clay as a carrier, has been found satisfactory. The com- 

 mercially prepared dusts vary in composition, but are usually based 

 on this pyrethrum-carrier mixture, sometimes with other substances 

 added. It is desirable to get as fine a dust as possible so that it will 

 remain suspended in the air for a long time, and it is also well to get 

 as light-colored a dust as possible, since darker dusts sometimes 

 settle on the mushrooms and render them unsightly, thus decreasing 

 their market value. 



