10 



BULLETIN 888, U. S. DEPARTMENT OF AGRICULTURE. 



Table II. — Results of dusting tests with pyrethrum powders and powdered stems against 



the dog flea. 





Active ingredients. 



Inert ingredients. 



Number 

 of dogs 

 treated. 



Per cent 



Test No. 



Per cent 



pyrethrum. 



Miscellaneous. 



of fleas 

 killed or 

 repelled. 



1 



4.00 



10.00 



12.59 



18.00 



32.63 



(?) 41. 00 



(?) 88. 00 



93.66 



100.00 



100.00 



100.00 



100.00 





Sulphur 



Sodium flourid and sand. . 



2 

 1 



1 

 2 

 2 

 2 

 2 

 2 

 1 

 2 

 1 

 1 

 2 

 1 

 8 



50-80 



2 





98 



3 



Naphthalene, 0.17 per cent 



30 



4 



Filler (?) . 



75-85 



5 







15-20 



6 



Cloves 



Borax 



100 



7 







100 



8 







100 



9 







100 



10 







100 



11 







100 



12 







100 



13 





Stems, 100 per cent 



o 



14 





o 



15 



i 



....do 



o 





I 







The low killing noted in tests Nos. 3 and 5 can be accounted for 

 on the supposition that the pyrethrum in these mixtures had dete- 

 riorated since it has been shown 13 that pyrethrum, exposed to the 

 air, loses practically all of its value in 150 weeks and when kept in 

 sealed glass containers is worthless after 5§ years. 



NAPHTHALENE. 



Table III shows the results of dusting tests with various percentages 

 of naphthalene against the dog flea. 



Table III. — Results of dusting tests with naphthalene against the dog flea. 



Test No. 



Per cent 



naphtha- 

 lene. 



Inert ingredients. 



Number 

 of dogs 

 treated. 



Per cent 

 of fleas 

 killed or 

 repelled. 



Remarks. 



1 



1.52 



6.48 



10.00 



12.17 



20.00 



40.00 



50.00 



59.21 



75.00 



100. 00 



100.00 



Lime 



2 

 2 



i 



i 



2 





 

 

 10-20 

 



Rubbed in. 



2 





Do. 



3 



Flour 



Not rubbed in. 



4 





Eubbed in. 



5 



Flour 



Not rubbed in. 



6 



do 



1 



Do. 



7 



8 



do 



1 



2 

 3 

 2 







50-60 



5-10 



50 



98-100 



Do. 



Rubbed in. 



9 



Flour 



Not rubbed in. 



10 



do 



Do. 



11 



do 



Rubbed in. 









Table III shows that naphthalene, which frequently has been 

 recommended against dog fleas, is effective, providing it is thoroughly 

 rubbed into the hair and that powders containing 75 per cent or less 

 are of little or no value. The table also shows very clearly the neces- 

 sity of working the powder well down into the hair, since a powder 

 containing 59 per cent (test 8) which was well rubbed in was as 

 effective as pure naphthalene (test 10) which was only dusted over 



i* Abbott, W. S. A study of the effect of storage, heat, and moisture on pyrethrum. U. S. Department 

 of Agriculture Bulletin 771. 1919. 



