654 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
In order to determine if a reasonable excess of nicotine would affect 
tender plants, different concentrations of Black Leaf 40 were used on 
tomato plants in the greenhouse. It was found that the plants were not 
injured after an interval of 2 days by a solution containing approximately 
3.5 per cent nicotine or about 50 times the concentration generally recom¬ 
mended. Solutions stronger than 3.5 per cent apparently injured the 
plants and the injury was more noticeable as the concentration was in¬ 
creased. 
Inasmuch as soap is commonly used in nicotine sprays, another set of 
experiments was made in which soap was added to the solution. This 
was found to partly prevent injury. 
It will be of interest for comparison to give the amounts of nicotine 
which were found in a much larger number of samples of common trash, 
especially of Burley, than were used in the spraying experiments. The 
samples used in that work, however, are included in the table. They 
were taken from the 1920 and 1921 crops but the latter crop of Burley 
was freer from disease, and a large number of the samples selected from 
it included mixed common filler and smoker grades which had a market 
value that would not permit their use for sprays. They would ordinarily 
be considered as common trash, however. As they had been used in 
connection with other work, the stem had been removed from all except 
15 samples of the Burley. 
Table 2- 
Burley, 63 samples. 
Dark (fire-cured) 10 samples 
Dark (air-cured) 6 samples. . 
1921 Crops. 
Common Trash of 
1920 AND 
aximum 
Minimum 
Average 
4.00 
0.26 
1.75 
4.50 
0.98 
3.06 
4.48 
2.16 
3.22 
The Burley sample containing 0.26 per cent nicotine may be excep¬ 
tional. If this is omitted, the range for 62 samples is from 0.67 to 4.00 
per cent, and the average 1.77 per cent. 
In order to illustrate the effect of disease on the nicotine and total 
nitrogen content of tobacco, two lots of Burley were selected. One lot 
consisting of 5 hands was appreciably infected and the other of 10 hands 
was very badly infected with wildfire. Representative samples of leaf 
with the stem present were taken from each hand of the two lots and 
individual nicotine and total nitrogen determinations were made. The 
remainder of each lot then had the stem removed and composite samples 
of each were used for analysis. The results follow: 
