New YorK AGRICULTURAL EXPERIMENT STATION. 319 
adults were numerous and were usually resting on the buds and 
bark of the unsprayed trees and on the treated trees when the wash 
was well dried. April 30, adults were still very plentiful. May 
30, adults were few in numbers; nymphs of the first, second and 
third stages were abundant upon the checks but were much less 
in evidence upon the sprayed trees. The axils of the fruit and 
leaf stems were beginning to be sticky with honey-dew and to 
have a sooty appearance. Ants were being attracted to the col- 
onies of psyllas, being in greater numbers upon the unsprayed 
trees. An abundance of ants upon a tree usually indicated a 
check and was one of the most conspicuous signs of psylla infesta- 
tion. On June 3, three and one-half rows of the untreated trees 
leaving 16 trees as checks, were sprayed with whale-oil soap to 
prevent the distribution of the psyllas throughout the orchard. 
June 27, eggs and nymphs of the first and second stages were 
abundant upon the checks and were to be found in greater num- 
bers than before upon the trees treated with the lime-sulphur 
wash. The rows sprayed with whale-oil soap had fewer insects 
than the checks. The leaves of the checks generally and a number 
of the trees in other parts of the orchard were well spotted 
with globules of honey-dew. July 18, all stages of the pear 
psylla were represented, but the numbers of the insect, compared 
with former observations, were much reduced; a few of the 
originally much infested trees were covered with a blackish slime 
while the remainder showed little evidence of psylla attack aside 
from the dirty, sticky condition of the axils of the leaves and 
fruits. The checks were as a rule clean; a few trees were quite 
sticky because of the honey-dew and a number of others had the 
axils of the leaves and fruits discolored with the blackish honey- 
dew. September 14, the pears were being picked. The yield of 
the fruit was not appreciably affected by the psylla attack. 
The pear psylla was not as numerous or as injurious as it had 
been during the preceding year. While abundant during the 
earlier part of the season this insect did not maintain its destruc- 
tiveness throughout the summer. For this reason no opportunity 
was given to estimate the full effects of the sulphur wash for 
this pest. The work accomplished indicates that the thorough 
applications of this mixture afforded protection to the trees 
against the first brood of psyllas but that further investigation 
