448 Report OF THE HORTICULTURIST OF THE 
“ oval cocoons of silk covered with grains of sand” (Smith.) This 
probably takes place any time from early spring to mid-summer, 
depending upon the locality, although in this State most of them 
go into the ground in June. They remain as pupe in the ground 
all winter, emerging as adults in the spring. Lawrence pears are 
especially liable to attack. 
Treatment.— This insect has proved a very difficult one to con- 
trol. Experiments have been made with a view to destroying the 
pup in the ground, but it has been found that in order to suc- 
cessfully. check the insect a dangerous amount of the insecticides 
tested must be applied to the soil. Hand picking, where practical, 
is probably the most satisfactory method of checking the insect. 
It should be done in June. 
OYSTER-SHELL BARK-LOUSE. 
This insect also has been discussed under apples, page 417. It 
is sometimes very injurious to young pear trees. 
PEAR PSYLLA. 
(Psylla pyricola Forst. ) 
Description.— This insect causes injury in two ways. First, by 
sucking the sap; second, by disfiguring trees and fruit. Its pres- 
ence is usually betrayed by the honey dew secreted by the young, 
wingless forms. The honey dew afterwards becomes covered 
with a black mold giving the leaves and twigs a black unsightly 
appearance. . 
The adult is an active four-winged insect measuring about one- 
tenth of an inch in length. It has been compared to a miniature 
seventeen year locust. A number of broods are produced during 
the summer, and the adults which live through the winter are 
distinct in form from the summer adults. They appear early in 
the spring and deposit their eggs in protected places on the bark. 
The eggs hatch within a few days and the little larvee, or nymphs, 
at once commence to suck the juices from the young leaves and 
