224 REpPoRT OF THE DEPARTMENT OF ENTOMOLOGY OF THE 
the axils of the leaves and at the base of the fruit stems. Within 
two or three days after hatching they cover themselves with 
honey dew which finally becomes so abundant as to disfigure 
leaves and fruits. The amount of injury done in this way 
varies of course with the number of the nymphs. When the 
nymphs are very numerous they take so much nourishment from 
the trees that the new growth is seriously checked. The whole 
tree assumes a stunted, unhealthy appearance. As a result the 
fruit crop is greatly lessened and in some cases trees have been ~ 
killed. Many trees weakened by the psylla last summer failed 
to survive the winter. 
TREATMENT. 
The young nymphs are the most easily reached. Close watch 
for them should be kept when the leaves are unfolding in the 
spring. As soon as the nymphs are found spray the trees 
thoroughly with kerosene emulsion, diluted with about ten parts 
of water or with a solution of whale oil soap, one pound to four 
to six gallons of water. The secret of success in fighting this 
insect is early and thorough spraying. It may be necessary to 
make two or three applications at intervals of three or four days 
to successfully control the pest. The orchardist should watch 
the results of the treatments to determine if the strength of 
the spray is satisfactory. Spraying should not be long delayed 
after the appearance of the nymphs, for it is much more difficult 
to kill them when once they are protected by the honey dew. 
PREPARATION OF SPRAYS. 
Kerosene emulsion.—Dissolve 14]b. finely divided common soap 
or whale oil soap in one gallon of water, preferably rain water, 
and while it is still boiling, remove it from the fire and add two 
gallons of kerosene. Then agitate the mixture violently by fore- 
ing it through a spray pump, back into the vessel again until 
it becomes a creamy mass that will not separate. For use, dilute 
as directed. 
Whale oil soap.—Whale oil soap may be purchased from the 
following’ manufacturers:—The Bowker Chemical Co., Boston, 
Mass.; James Good, Nos. 939 and 941 North Front Street, Phila- 
delphia, Penn.; Poole & Bailey, No. 357 Canal Street, New York 
city; W. H. Owen, Catawba Is., Ohio. tee 
