TESTS WITH INSECTICIDES UPON GARDEN INSECTS. 
By William B. Alwood, Special Agent. 
LETTER OF TRANSMITTAL. 
Columbus, Ohio, October 30 , 1886 . 
Sir : I inclose herewith a summary of my tests with different insecticides. These 
are not written in the style of a report, hut to acquaint you with the results I have 
obtained. My work is just begun, and I do not feel as though anything creditable 
in the way of a report could be furnished so far. I trust this will be satisfactory 
and furnish you with what information you desire concerning the progress of the 
work thus far. If yon desire it I can furnish a copy of the original notes from 
which this summary is made up; however, many of my serial tests were noted in bulk 
instead of keeping an individual record of each test. This was done because of same- 
ness and lack of importance in the individual record. This matter would have 
reached you a week sooner had I not been ill for several days. I will forward some 
notes about machinery in a few days. 
Very respectfullv, 
WM. B. ALWOOD 
Prof. C. Y. Riley, 
U. S. Entomologist. 
KEROSENE EMULSION. 
Formula. — Kerosene, 67 per cent. ; water, 33 per cent. ; whale-oil 
soap sufficient to form a stable emulsion. 
This preparation was used on several insects with somewhat varying 
results, the chief features of which are condensed in this note. 
On Cabbage Worms. 
The first series was begun before Plusia brassicce was numerous, hence 
only Fieris rapw is spoken of. The emulsion was used in different di- 
lutions, ranging from equal parts of water and emulsion to 16 parts of 
water and 1 of emulsion. It was in all cases applied as a spray, and 
when the worms were numerous and eating vigorously. Several hun- 
dred plants were used in the field tests. Weaker solutions than 1 of 
emulsion to 3 of water were of no avail unless applied very heavily, and 
then they caused considerable injury to leaves. In the proportion of 1 
to 3 it was quite effective where the worms could be reached, i. e., were 
not under the leaves, and destroyed about 75 per cent, of them. It did 
not injure the leaves in this strength if properly sprayed. Where so- 
lution of 1 to 5 was put on excessively it killed and also injured plants. 
Stronger solutions than 1 to 3 were not more efficacious and injured 
plants seriously. The weaker solutions would sicken the worms and 
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