220 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 14 



1 per cent, nicotine in another case and 3 per cent, nicotine in still another 

 case in comparison with the effect of three-fourths of a pint of nicotine 

 to 50 gallons of commercial liquid lime sulfur spray, both of the delayed 

 dormant and siimmer dilutions. 



Species 

 cf Lice 



Aphis avenae 



Killing Agent 



Nicotine 

 Dust, 5% 



" 1% 



•' 3% 

 L— S 1 to 40 

 L — S 1 to 40 Nicotine 

 40% K pts. to 50 gals. 



4-29-'20 



Dust. 5% 



" 1% 



" 3'V 

 L— S 1 to 40 Nicotine 40% 

 H pts. to 50 gallons 

 L— S 1 to 40 



L — S 1 to 40 Nicotine 40% 

 J^ pts. to 50 gallons 



The first section of the above table shows the comparative results of 

 nicotine impregnated 90-10 dust and the delayed commercial lime- 

 sulphur nicotine spray on the oat aphis but gives no data whatever of 

 their relative effects upon the eggs because practically all specimens 

 had hatched before the delayed dormant applications were made. 



Both the first and second sections show, however, that while recently 

 hatched aphids are more efficiently reduced by liquid treatments the 

 90-10 dust impregnated with one percent, or more of nicotine do very 

 material execution indeed. 



President W. A. Orton : The next paper is by Mr. A.L. Quaintance. 



DUSTING VERSUS SPRAYING OF APPLES 



By A. L. Quaintance, Entcmologist in Charge Fruit Insect Iniestigations, Bureau 



of Entomology 



Different workers have recently rather fully simimarized results of 

 dusting apple orchards in comparison with spraying and reference to 

 these experiments is here unnecessary, even were the time allotted me 

 sufficient for this purpose. It is also quite unnecessary to dwell on the 

 advantages, if effective, of dusting over spraying of orchards, since these 

 advantages have been frequently pointed out and are furthermore 

 perfectly obvious to any one experienced in orchard work. 



It is the purpose of the present brief note to present in tabular form 

 some results obtained by the Bureau of Entomology and Bureau of Plant 



