78 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



The advantages of nicotine delivered as a dust over nicotine delivered 

 88 a spray are mainly concerned with the speed at which the acreage can 

 be covered and the freedom from the necessity of securing water supply 

 nearby. 



The disadvantage of nicotine delivered as a dust as above set forth 

 must in all probability be met primarily through discovering a carrier 

 which will deliver the nicotine at a more rapid rate and in larger amounts, 

 or through the discovery of a carrier which will by attaching itself more 

 closely to the body of the insect render the nicotine which it does deliver 

 more effective, or through the discover\^ of a carrier that will operate 

 along both these lines. 



Table 2 will serve to show the results of certain field tests made with 

 different carriers. 



Table II. — Table Showing the Effect of Certain Nicotine Dusts on Macrosiphum solani- 

 FOLn ON American Giant Potatoes and on Tomatoes 



Date of Composition of Dasts No. of lbs. 



treatment Material % Material % Material % Material % per acre 



In dealing with the pink and green aphis on potato and tomato it 

 seems useless to consider a higher percentage of nicotine than 2% 

 because che cost of the material becomes impracticably high. There is, 

 however, no doubt that as the charge of nicotine is increased the kill of 

 the lice also increases within the limited period, but the increase in kill 

 is not in proportion to the increase in cost. This fact is shown in 

 Table 3. 



