BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 
11 
Rob.) were released in the spring of 1940. in several States and 
the District of Columbia. In addition. 2,500 females of T. vt rnalis 
were furnished the University of Maryland for use in a program of 
mass rearing for subsequent liberation. 
THE PEAR PSYLLA IN THE NORTHWEST 
A program for the suppression of the pear psylla in the Pacific 
Northwest was undertaken in cooperation with State agencies in 
Washington and Idaho, with funds allotted from the appropriations 
for the control of incipient and emergency outbreak- of insert pe^ts 
and plant diseases. During July 1939 the pear psylla, an extremely 
destructive insect which has been present in the northeastern part 
of the United States for more than 100 years, was found for the first 
time in the Pacific Northwest in a very limited area in Washington 
and Idaho, near Spokane. Wash. Cooperative surveys participated 
in by various State agencies failed to reveal its presence in the main 
pear-producing areas of Washington. Oregon, and Idaho. 
The area in which the insect was first found in the Northwest 
appeared to be limited in extent to approximately 225 square miles 
and to involve not more than 12,000 pear trees, mostly in dooryards 
or small home orchards. Because of the comparatively small num- 
ber of trees concerned, and the presence of mountain or desert bar- 
riers between the infested district and the important pear-producing 
areas, the chances appeared favorable for preventing the spread of 
the insect and for its ultimate eradication from the Northwest. 
An organization was set up at Spokane in February 1940 to deal 
with the problem. Intensive scouting early in the season of 1940 
revealed that light infestations existed on additional properties in 
the Spokane Valley, which increased the area involved To 4.500 
square miles and increased the number of trees involved to about 
28,000. The infested area is still reasonably well isolated, and ulti- 
mate eradication of the insect still appears feasible. 
An intensive program of spraying is under way. and the infes- 
tation has been markedly reduced. The cooperating States have 
promulgated quarantines to prevent the accidental movement of the 
insect in a number of farm products grown or packed near infested 
pear trees. A great many individual trees have beeen removed by 
the owners or under waivers signed by the owners. 
Several laboratories of the Division have made contributions to 
the program. The personnel of the Yakima. Wash., laboratory 
surveyed the upper Yakima Valley during the summer of 1939, and 
this survey is being repeated during the summer of 1940. The 
Moorestown, N. J., laboratory conducted numerous experiments with 
fumigation with methyl bromide against the pear psylla. The insects 
needed for this work were furnished partly by the New York 
Agricultural Experiment Station at Geneva and partly by the 
Bureau laboratory at Poughkeepsie, X. Y. On the basis* of infor- 
mation obtained, farm product- which may be infested are being 
allowed to move out of the infested areas' in the Spokane Valley 
after fumigation. 
