424 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
TOBACCO DUST AS A CONTACT INSECTICIDE 1 
By P. J. Parrott and G. F. MacLeod, 
New York Agricultural Experiment Station , Geneva, N. Y. 
Abstract 
From the data secured during experimental work reported on the following pages, 
it is concluded that the finer grades of tobacco dust, containing 1 percent nicotine, 
are highly toxic to the spirea aphis (Myzus persicce). Observations of the spirea 
plantings under treatment during the past two seasons also indicate that timely 
applications of fine tobacco dust would afford adequate protection. In comparison 
with superfine tobacco, dust mixtures containing free nicotine or nicotine sulfate 
were, on an average, somewhat more effective but the actual difference in toxicity 
was not marked. 
As the tests were made in greenhouses it is not safe to conclude that finely pow¬ 
dered tobacco would prove equally effective against the same insect under normal field 
conditions. The insecticidal properties, however, are such as to suggest the de¬ 
sirability of more knowledge of the value and economy of the material in combating 
other noxious species. 
In conclusion it should be noted that commercial grades of tobacco show a lack 
of standardization since they vary greatly in nicotine content and physical properties. 
Considering the nicotine content of tobacco dust and commercial brands of tobacco 
extracts in relation to prices, powdered tobacco is apparently more expensive than 
the commercial solutions. 
In considering the merits of dusting as related to orchard management 
in New York, there is need of experimental data regarding the value of 
dust mixtures in combating such insects as the green apple aphis, rosy 
aphis, leafhoppers, redbugs, pear psylla etc. To combat insects of this 
character there is not a wide range of available substances with desirable 
insecticidal properties. At present nicotine sulfate is widely used and 
recently free nicotine has been recommended for the control of certain 
species. These are certainly the most effective constituents of dust 
mixtures which function as contact insecticides, but a serious drawback 
to their extensive employment is their high cost. The situation reveals 
the desirability of more knowledge concerning the toxic properties of 
other substances. 
Of the materials considered deserving of more serious consideration 
than has apparently been devoted to it is tobacco dust, and during 
the past two years the Geneva Experiment Station began a serious 
investigation to determine its value in combating the common sucking 
insects of orchard and farm crops. This paper deals largely with the 
more important results of tests with tobacco dust against the aphis 
{Myzus persicce Sulz.) on spirea {Caryopteris mastacanthus ), a plant 
which is grown extensively in greenhouses of local nurseries. 
Presented at the Meeting of the Division of Agricultural and Food Chemistry 
of the American Chemical Society at New Haven, Connecticut, April 4, 1923. 
