18 
New Bickmond, Ohio, kerosene in an undiluted form had been used with 
marked success both in 1895 and in 1896, "without the least injury to 
the trees, either apple or peach. * * * Where the top was seriously 
infested with scale this was cut away and burned, the trunk painted 
with kerosene, and at the proper season grafts were placed in the stubs 
of the old limbs that had been left sufficiently long for the purpose. In 
this case a new top has been grown on the old trunk, often a more sym- 
metrical top than the original, the tree thereby losing but little by reason 
of the attack by the scale. Last July I went through the orchard and 
found many of the trees thus treated growing nicely and free from 
scale. * *. * Where trees were known to be slightly infested, or as 
a means of killing the scale on any trees not known to be infested, an 
entire orchard, consisting of both apple trees and peach trees, was 
sprayed with undiluted kerosene during February, and in order to make 
sure that no scale escaped alive a second application was made shortly 
after. I saw the orchard in April and again in July, and in neither 
case did I notice any injury whatever to the trees, either apple or 
peach." 
This statement by Mr. Webster occasioned much comment among the 
entomologists in attendance at the meeting, and several of them soon 
after began experimental work. The result of the experiments carried 
on in this Division were summarized by Mr. Marlatt in a paper pre- 
sented to the Association of Economic Entomologists at its Detroit 
meeting in August, 1897, and are here quoted: 
The discussion of this substance at the last meeting of the association led to some 
additional experiments on our part with the use of pure coal oil or kerosene on plants. 
Various trees, including young and vigorous peach, pear, cherry, and apple trees, 
euonymus bushes, and some old bearing peach trees, were thoroughly sprayed with 
pure kerosene early the past spring, with one exception, before the buds had begun 
to swell. In the case of two large bearing peach trees the blossom buds were swell- 
ing and opening, and these trees were also badly infested with Diaspis lanatus. The 
other plants, with the exception of the euonymus bushes, were healthy and free 
from all insects. Much to my surprise and astonishment, no ill effects of any moment 
resulted in the case of any of the trees sprayed with kerosene. In the case of all 
the trees spraying was continued just long enough to moisten the plants thoroughly, 
but not to cause the oil to run down the trunks and collect about the base ; and with 
the young trees the soil was carefully mounded up and pressed about the crown to 
avoid all danger of the oil collecting at that point. 
The pear trees treated, and also the peach, came out in full bloom, the opening of 
the blossom buds not being at all interfered with by the oil bath. After the bloom 
fell the peach trees treated with pure oil made much finer growth than untreated 
trees. This may have been in part due to the more favorable location of the trees, 
and possibly also to the fact that in the treatment with the coal oil the eggs of 
Aphides on the trees had been entirely killed, whereas on the untreated trees a very 
bad infestation with plant lice developed early and checked the growth of the trees, 
killing some of them. No Aphides, however, appeared on the sprayed trees. In the 
case of the pear trees particularly, and also the apple, the unfolding of the leaf 
buds was very noticeably delayed as compared with untreated plants, the buds 
seeming to open up much more slowly, and for two weeks at least the difference was 
very marked. Very soon thereafter, however, the treated trees overtopped the 
