EXPERIMENTS AGAINST CARPET BEETLES. 



33 



when diluted not more than 1 part to 10 parts of water. Against 

 eggs, in two tests each, a 3, 5, and 10 per cent solution of crude car- 

 bolic acid appeared to prevent hatching. 



Effect on carpet-beetle larva? and eggs. — Fish-oil soap, used at the 

 rate of 1 pound to 4 and 8 gallons of water, killed 100 per cent of 

 the larva?. When used at the rates of 1 pound to 10, 16, and 25 gal- 

 lons, from 75 to 90 per cent were killed, while weaker solutions 

 proved ineffective. Practically the same results were obtained by 

 the use of laundry soap. 



Laundry soap, used at the rate of 1 pound to 10 gallons of water, 

 appeared to kill all carpet-beetle eggs in two tests. When used at 

 the rates of 1 pound to 20 and 40 gallons of water it was not effective 

 against the eggs. 



NICOTINE SOLUTIONS AND TOBACCO POWDEES. 



Effect on carpet-beetle larvm. — Table VIII shows the results of 

 tests with nicotine in various forms against the carpet-beetle larvae. 



Table VIII. — Tests of the killing effect of nicotine solutions and tobacco 

 powders upon carpet-beetle larvw. 



Ex- 



Nicotine, amount and form. 



Dilution in 

 water. 



Number 

 of tests. 



Treated. 



Un- 

 treated. 



peri- 

 ment 

 No. 



Total 

 number 

 of larvae 



used. 



Average 



per cent 



dead. 



Average 



per cent 



dead. 



1 





ItolO 



lto25 



Ito50 



lto25 



Ito50 



1 to 100 



1 to 125 



lto32 



Undiluted 



do 



2 



2 

 2 

 2 



4 

 2 

 3 



8 



2 

 2 



20 

 20 

 20 

 20 



40 

 20 

 30 



80 



20 

 20 



100 

 60 

 20 

 75 



47.5 

 5 

 70 



72.5 



5 

 5 



6 



2 



do 



6 



3 



.do 



6 



4 



40 per cent nicotine as extract in nicotine- 

 water solution. 

 . . .do 





5 





6 



do 



12.5 per cent nicotine in nicotine- water solu- 

 tion. 



11.6 per cent nicotine in nicotine- water solu- 

 tion. 



4.56 per cent nicotine in tobacco dust." 



0.41 per cent nicotine in tobacco dust 





7 

 8 

 9 



10 

 4 



10 













As will be noted, it was necessary to use a tobacco extract (40 per 

 cent nicotine, as sulphate) diluted at the rate of 1 part to 10 parts of 

 water to kill all the larvae. All weaker dilutions used failed to kill 

 more than 75 per cent. It is therefore apparent that nicotine sprays 

 are not to be recommended for carpet-beetle larvae. 



Powdered tobacco, containing 4.56 per cent of nicotine, which is 

 considerably above the average percentage of nicotine content for 

 such powders, was ineffective against the larvae when used as a dust. 



