New YorK AGRICULTURAL EXPERIMENT STATION. DEG 
and in addition this application caused the bark to become 
spongy. 
Spongy bark does not always occur. From observations in 
other orchards where crude petroleum was used, the indications 
are that sunlight and heat acting on the coating of vaseline, 
have something to do with producing this condition. 
It is fair to state that most of the above pear trees recovered 
from the treatment. By the latter part of June they are covered 
with new foliage, and as Dr. Smith’ says “ The oil seems to have 
acted as a stimulant, the sprayed trees have shown greater vigor 
and better foliage than those untreated.” The latter condition 
apparently resulted from the development of latent buds, which 
formed numerous small, undesirable branches. It is a question 
whether these branches were not of the same nature as what are 
called “ water-shoots ” indicating weakness of trees. 
Tests made in the winter of 1900-1901 show: First, that the 
use of a 15 per ct. mechanical mixture of crude peroleum, specific 
gravity 0.79, on peaches in December destroyed all fruit buds, 
and a 25 per ct. mechanical mixture killed the trees outright. 
Badly infested plums treated at the same time and in same man- 
ner with same grade of crude petroleum were somewhat injured; 
while apple trees treated on same dates with same amounts and 
grade of crude petroleum were not injured in the least. 
Second, that neither a 15 nor a 25 per ct. mechanical mixture 
of crude petroleum, specific gravity 0.79, applied to peach and 
plum in April, or after the buds commence to swell, produced 
any injury; while the same amounts and grade of crude petro- 
leum applied to apple and pear on same dates, slightly injured 
apple and destroyed nearly all fruit buds on pear. 
Third, that two applications of crude petroleum, specific 
gravity 0.79 in either 15 or 25 per ct. mechanical mixtures, dur- 
ing the same winter are fatal to peach, very injurious to apple 
and slightly injurious to plums (Japanese varieties). Possibly in 
this case, the principal injury to the peach may have resulted 
from the December treatment, and conversely the major portion 
of the injury to the apple trees may have resulted from the April 
treatment. 
™N. J. Agr. Exp. Sta. Bul.*138, p. 20. 
