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ST 
REPORT OF THE STATE ENTOMOLOGIST 1901 
trees till the autumn of 1900, when trees 12, 13 and 14 were very 
badly infested; and, on account of this close proximity to trees. 
in a similar condition on which the scale bred unchecked during 
the entire season of 1900, it is very probable that they became 
reinfested during the growing season, and therefore their con- 
dition Sep. 25, 1901, should not be taken into account when judg- 
ing of the merits of whale oil soap; and the same would be true, 
but to a less extent, of trees 31-33. Even after throwing these 
trees out of consideration, the results are not equal to those 
obtained with mechanical petroleum emulsions, though the pest 
was well controlled. 
Summary of experiments 
A study of the above records will show that the best results. 
have been obtained with either a 20% or a 25% mechanical emul- 
sion of crude petroleum. Apparently somewhat better results 
were obtained by the use of the oil purchased from the Standard 
oil co., but this may be partly accidental. It is a trifle early to 
be positive regarding this point. It is certain, however, that 
either the Standard oil or the crude petroleum obtained from the 
Frank oil co., Titusville Pa., will give very satisfactory results. 
The whale oil soap and crude petroleum combinations were very 
effective, but were not so valuable as insecticides as mechanical 
petroleum emulsions. None of these preparations injured the 
trees in the slightest degree. 
The experiments with the whale oil soap solutions show that, 
while this substance is valuable as a check, it can hardly be relied 
on when applied in early spring to do anywhere near so thorough 
work as the crude petroleum emulsions. The reason for the 
greater efficiency of the crude petroleum is probably found in the 
greater penetrative action of the oil. The few tests with the 
undiluted crude petroleum confirm the experience of the previ- 
ous year and lead us to conclude that it is a very unsafe substance 
to apply to trees. 
