INSECTICIDES AND REPELLENTS 



61 



directions as possible, front and back. In deJousing women an extra 

 quantity may be blown down the neck of the dress and application 

 at the waistline omitted. About \){ ounces per person is sufficient 

 for winter dress. The hair, hat or cap, extra clothing, and bedding- 

 should be included. One such treatment with DDT is generally 

 adequate to control infestations. 



Powder containing 1 percent of lindane has been approved for 

 military use in areas where DDT-resistant lice are encountered. 

 This material was used successfully on a large scale in Korea after 

 DDT powder became ineffective. Directions for its application are 

 the same as for DDT powder. However, since it is not so long- 

 lasting, a second application within 7 to 10 days is advocated. 



The MYL powder was developed before DDT became available. 

 The original formula contained 0.2 percent of pyrethrins, 2 percent 

 each of JV-isobutylimdecylenamide (synergist) and 2,4-dinitroanisole 

 (ovicide), and 0.25 percent of Phenol S (antioxidant). Upon the 

 discovery of DDT-resistant lice in Korea, further tests were made with 

 this preparation and the formula was slightly changed by reducing 

 the amount of Phenol S to 0.1 percent and substituting sulfoxide as 

 the synergist. One type also contained 0.3 percent of allethrin in 

 addition to the pyrethrins. 



The MYL powder has a very rapid action on the lice. In tests at 

 Orlando they were all immobilized within 15 minutes, and unable to 

 take blood meals after 10 minutes. On cloth impregnated with 

 DDT, a 2-percent solution or a 10-percent dust, lice continued to 

 feed for 1 or 2 hours. 



Figure 24. — GI applying DDT to underwear from a sifter-top can for louse 



control. 



