Resistance to Insecticides 



In many areas bed bugs have be- 

 come resistant to DDT, and other 

 insecticides must be applied. 



In some of these areas lindane con- 

 trols the DDT-resistant bugs, bur in 

 so, nc localities the bugs have de- 

 veloped resistance ro this insecticide 

 also. 



Malathion and pyrethrum are effec- 

 rive against bed bugs, and no resis- 

 tance to them has been observed 

 (September 1959). 



increase the effectiveness of the pyreth- 

 rum. The sprays should contain at least 1 

 percent of one of the synergists. 



Pyrethrum usually kills bed bugs quicker 

 than DDT, but it is not nearly as long 

 lasting. Many household-type pyrethrum 

 sprays contain 2 or 3 percent of DDT, 

 which makes them longer lasting. Ready- 

 to-use combination sprays of this type 

 are widely available and are very effec- 

 tive against bed bugs and certain other 

 household pests. 



How To Use Sprays 



A single treatment with a DDT, lin- 

 dane, or malathion spray, or with a py- 

 rethrum-DDT spray, usually controls bed 



bugs in a room and leaves a deposit 

 thai prevents reinfestation for several 

 months. Since it is impossible to pene- 

 trate all the hiding places, control is not 

 complete or immediate — a few living 

 bugs may be seen for a week or 10 days 

 after the treatment. If you continue to 

 see bugs after 2 weeks, spray again. 



You can control bed bugs with a spray 

 containing only pyrethrum; but since 

 such a spray does not leave a long-lasting 

 deposit, several treatments 1 or 2 weeks 

 apart are required. 



Effectiveness of control depends on the 

 thoroughness with which spray is ap- 

 plied. To treat a bed— 



• Spray the slats, springs, and frame. 

 Apply enough spray to wet them 

 thoroughly. Do not miss any of the 

 crevices where bugs hide. 



• Apply a light mist spray to the en- 

 tire mattress. Penetrate seams, tufts, 

 and folds. 



About 4 ounces of spray usually is re- 

 quired to treat a bed and mattress. Al- 

 low 1 to 2 hours for the bed to dry before 

 putting on sheets or occupying it. 



Spray upholstered furniture thoroughly. 



In treating other hiding places, apply 

 enough spray to penetrate all crevices 

 and to wet all surfaces to the point of 

 runoff. Spray walls to a height of sev- 

 eral feet above the floor. 



Guide for Mixing Sprays 



Insecticides (as emulsifiable liquids) and certain of the 

 strengths in which they may be purchased 



Percentage of 

 insecticide de- 

 sired in spray 



Amount of emulsifiable liquid 



to mix with 1 quart of 



water or kerosene 



DDT, 25 percent. . . . 

 Lindane: 



20 percent 



12 percent 



Malathion. 50 percent. 

 Pyrethrum. 1 percent 2 



5.0 



'0.5 

 0.1 



'0.5 

 0.1 



1.0 

 -0.2 



8 ounces 



2 tablespoons 



1 teaspoon 



3 tablespoons 



2 teaspoons 



4 teaspoons 

 8 ounces 



1 For application to hiding places only. Apply lower concentrations on mattresses. 



2 Refers to pyrethrins content. 



