EXPERIMENTS AGAINST CLOTHES MOTHS. 



25 



4 per cent of nicotine, this substance should not be depended upon 

 for protection of clothing against moth attack. 



No tests with nicotine extract were made to determine its value 

 in protecting clothing from moth infestation in the presence of 

 adults. 



Effect on Icuruce. — In Table IV are shown the results of 18 tests 

 with several forms of nicotine in varying dilutions. 



Table IV.- 



-Tests of the killing effect of nicotine solutions and tobacco powders 

 against clothes-moth larvce. 





Nicotine, amount and form. 



Dilution in water. 



Treated. 



Untreated. 



Test 

 No. 



Number 



oflarvse 



used. 



Per cent 

 dead. 



Number 



oflarvee 



used. 



Per cent 

 dead. 



1 





1 to 125 



20 

 10 

 20 

 20 

 20 

 20 

 10 

 20 

 10 

 20 

 10 

 10 

 20 

 20 

 20 

 20 

 20 

 20 



5 



40 



20 



10 



5 



130 



10 



10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 56 

 50 

 10 

 50 



20 



2 





1 to 125 



10 



3 





1 to 32 



20 



4 





1 to 32 



10 



5 



.do 



1 to 32 



40 



6 





1 to 100 



20 



7 





1 to 100 



10 



8 



.do 



1 to 75 



15 

 20 

 30 

 30 

 50 

 55 

 5 



20 



9 



.do . . 



1 to 75 



30 



10 



do 



1 to 50 



30 



11 



...do 



1 to 50 



20 



12 



.do 



1 to 25 



40 



13 



do 



1 to 25 



30 



14 



15 



0. 41 per cent in tobacco dust 



Undiluted 



do 



6 



16 





. .do 





8 



17 





do 



10 

 20 





18 



4. 56 per cent in powdered leaves . . . 



do 



6 



1 Of those dead, 25 per cent probably drowned, as water was found in the jar. 



It is seen that every form of nicotine, at the dilutions used, failed 

 to kill an appreciable number of larva?, and since the greatest 

 strength used was 1 part of tobacco extract (40 per cent nicotine, as 

 sulphate) to 25 parts of water, it is apparent that to kill a higher 

 percentage the preparation would have to be used very slightly 

 diluted or undiluted. This evidently would not be practical on ac- 

 count of the comparative cost and the danger of staining woolens. 



Effect on eggs. — A nicotine-water solution (40 per cent nicotine), 

 used at the rates of 1 part of the mixture to 25 and to 50 parts of 

 water, killed all of the eggs on sprayed flannel. When the propor- 

 tion of water was increased to 75 parts, 2 eggs hatched in one test and 

 none in the other. The two larvae resulting from the hatched eggs 

 died almost immediately. When a dilution of 1 to 100 was used in 

 2 tests, one egg hatched in one test and two in the other, the resulting 

 larvae dying almost immediately. No greater dilutions were used, 

 but the results indicate that when used at a much greater dilution 

 than 1 to 100, the material would not be effective against the eggs. 

 Owing to the expense of such a substance its use would be prohibitive. 



