8 BULLETIN 888, U. S. DEPARTMENT OF AGRICULTURE. 



4. Mercurial ointment, applied around or just below the vent of 

 the fowl, was very effective, and vaseline and paraffin were of no 

 value when applied in the same way. 



5. Forty-five chicken-lice powders containing naphthalene, nico- 

 tine, pyrethrum, sulphur, and phenols proved to be effective when 

 the active ingredients were present in ihe necessary amounts. 



6. Powders containing nicotine, naphthalene, and sulphur were 

 effective against chicken lice when added to the dust bath. Lime- 

 sulphur added to the drinking water and one powder which was 

 mixed with the food had no effect on the lice. 



7. Pyrethrum powder was very effective, and pyrethrum stems of 

 no value against chicken lice. 



8. Tobacco powders containing not less than 0.75 to 1 per cent 

 of nicotine are of some value but do not kill all of the lice. About 

 1.5 per cent is required for the best results. 



9. A powder containing 10 per cent of naphthalene was effective 

 against these pests but slightly injured the fowls, and 60 per cent 

 killed the birds when well rubbed in. Naphthalene sprinkled over 

 the backs of fowls at roost proved to be of considerable value against 

 chicken lice. Naphthalene nest eggs were of no value against lice 

 and proved injurious to sitting hens. 



10. Thirteen miscellaneous powdered materials were tested and 

 found to be effective and 26 ineffective against chicken lice. 



RECOMMENDATIONS. 



Since chicken lice breed on the body of the fowl, it is necessary to 

 treat each and every bird in the flock for the control of these pests, and 

 no treatment of the roost, dropping boards, or chicken house can be 

 of any value. 8 



The following insecticides have been found to be very effective: 



Mercurial ointment. 9 — -This remedy is prepared by mixing 1 part 

 of mercurial ointment (50 per cent metallic mercury) with 1 or? 

 parts of vaseline, lard, or some other carrier of like consistency. A 

 lump of this ointment about the size of a pea is rubbed into the skin 

 just below or around the vent and an equal amount under each wing. 

 A slight reddening of the skin may result, but no permanent injury 

 has been noted. 



Sodium Jiuorid. 10 — This material, used as a dust or as a dip at the 

 rate of 1 ounce commercial or f ounce chemically pure sodium 

 fluorid to 1 gallon of water, has been found to be very effective. 



Sulphur. — Used freely as a dust, sulphur forms a cheap and very 

 effective lice killer. 



s This house treat mention the other hand, is absolutely essential for the control of the chicken mite, 

 Dermanyssus gallinse Redi. 



9 For a full account of experiments with this material see Lamson, G. H., and Manter, J. A., op. cit. 

 io See Bishopp, F. C, and Wood, H. P., op. cit. 



