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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
and simplest remedy. After the larvae work down the stems it will be 
more difficult to locate them, the stems may look green and healthy but 
the borings or trass in the center of the stem will show that the larvae 
have not been reached. Cut below this area and burn cuttings. 
THE PREPARATION FROM TOBACCO OF A SOLUTION 
FOR SPRAYING 1 
By O. M. Shedd and A. J. Olney, Kentucky Agricultural Experiment Station 
Abstract 
The only grade of Kentucky tobacco, other than stems and stalks, which can be 
used profitably at present prices for making a spray solution is common trash. This 
is chiefly composed of diseased and damaged leaf. It has a widely variable and 
generally low nicotine content but usually contains more than stems and stalks of 
the same variety. The range for 79 samples of white Burley and dark tobacco was 
from 0.26 to 4.50 per cent nicotine in the air-dry trash. 
Angula r leaf-spot and wildfire lower the nicotine content but not the nitrogen 
content of the leaf. The nicotine content of the leaf which cured with a green color 
was not affected to the same extent as that of diseased leaf. 
Infusions made from 26 samples of trash, using such quantities of cold water as 
would give .05 to .07 per cent of nicotine in the solution, as computed from analyses 
of the samples, were about equally effective in exterminating aphis. Lower concen¬ 
trations were not as satisfactory. 
Black Leaf 40 solution diluted to contain 3.5 per cent of nicotine did not injure 
tomato plants. Higher concentrations caused injury which was partly preventable 
by soap. 
It is important that the approximate nicotine content of trash used to make a 
spray solution should be known. If it is not, then a low percentage of nicotine must 
be assumed. This probably should be about 1 per cent for white Burley and 1.7 
per cent for dark trash grown in Kentucky. 
The object of this paper is to emphasize the importance of having some 
knowledge concerning the nicotine content of tobacco which is to be 
used for the home preparation of a spray solution. This should be given 
first consideration and if it is disregarded, unsatisfactory results will 
frequently be obtained and this may create prejudice against all such 
preparations, including commercial nicotine solutions which undoubted¬ 
ly have demonstrated their merit. 
Nicotine is the characteristic alkaloid of tobacco and is a very power¬ 
ful poison, particularly for certain insects. A solution of it has the 
peculiar advantage that a moderately excessive amount does not injure 
Approved by the Director of the Kentucky Agricultural Experiment Station, and 
read at the symposium on insecticides and fungicides of the American Chemical 
Society at their meeting in Washington, D. C., April 21-25, 1924. 
