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others hoth in abundance of foliage and amount of new growth, and at tlie present 
writing (.July 20) there seems to have been BO injury whatever as a result of the 
treatment. 
The large peach tree sprayed showed no ill effects, and all of the scales on the 
tree were killed except where they had l»een protected in a few in>fanres l>y ma--«-s 
of leaves webbed about the limbs. At least 99 per cent of the scales were killed. 
On the euonymus a similar result was shown, at least 99 per cent of scales having 
also been killed by the oil. 
These results are so greatly in contrast with those previously attained in the 
experiments conducted in practically the same way that it seems difficult to 
account for them. That spraying with pure oil will often kill trees can not be 
doubted, even when applied in the dormant condition in winter, as demonstrated by 
experiments on a number of apple and peach trees two or three seasons ago. It is 
possible that with these earlier experiments the same care was not employed to pre- 
vent the collection of oil about the trunks of the trees, and the trees were not 
mounded up, but the work was as carefully done as would ordinarily be the case in 
actual practice, and probably much more so. It is possible, therefore, that the death 
of the trees in some instances was due to the collection of the oil in the cavity 
formed about the trunk by the swaying of trees in the wind, which, as will be shown 
later, has had disastrous results in California with the emulsion even. Others have 
reported the use of oil on trees without injurious effects in some instances, and in 
others with injurious effects, so that pure oil as an insecticide is one to be used with 
caution and with full appreciation of the fact that the death of the plant may 
result. 
An earlier result came to the Division by correspondence, when in the 
first week in March, 1897, the Messrs. Parry, of Parry, X. J., sent in 
cuttings of dwarf pears which it was said had been sprayed with pure 
kerosene oil and which had a distinct kerosene odor upon receipt. 
Examination, probably about a week after the spraying operation, 
showed that of 100 scales selected at haphazard from the twigs, 51 
were dead and 49 were still living'. This was not encouraging, but no 
details were given by Messrs. Parry as to the method of spraying. 
September 1. 1897. Prof. J. B. Smith issued a circular headed •• Treat- 
ment for the San Jose Scale,' 7 in which it was stated that although his 
1897 experiments with insecticides against the San Jose scale were not 
yet completed, the results obtained up to that date indicated the desir- 
ability of a change in the treatment heretofore recommended, lie 
indicated that instead of winter applications summer work would 
prove most satisfactory and undiluted kerosene the most effective 
insecticide. The following sentence was published in large type: 
"Spray thoroughly in September all infested bearing apple, pear, plum, 
and peach trees with undiluted keroseue. during the middle of a clear, 
sunshiny day." Treating nursery stock and very young trees with 
undiluted kerosene was not recommended. The statement was made 
that the scales will continue active throughout September, and that 
kerosene had proved uniformly fatal to all stages in all experiments 
made up to that time. No injury had been caused on any treated trees 
except on plum after a spraying made in early spring, and this injury 
was temporary. The ordinary burning fluid used in lamps was the 
substance recommended, and it was said that it should be applied "in 
