MONTHLY LETTER OF THE BUREAU OF ENTOMOLOGY 
UNITED STATES DEPARTMENT OF AGRICULTURE 
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December, 1916. 



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ACTIVITIES OF THE BUREAU OF ENTOMOLOGY. 
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LIBRARY 
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(From the Report of the Secretary of Agriculture 





CONTROL OF INSECTS. 
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"While all the State Experiment Stations support work in ec : e-ENeOOT OR, — 
while many other countries are developing services in this direction, the Department 
of Agriculture has by far the largest organization for the purpose of research on in- 
‘sect pests. It is virtually the leader of the world in the warfare against injurious 
insects. It has in its files biological notes on thousands of species and is study- 
ing them from all points of view in its field laboratories. No less than 143 distinct 
‘projects are teing investigated at the present time, involving possibly 500 of the 
| species of insects most injurious: to crops, domestic animals, stored foods, forest 
products, shade. trees, and ornamental plants. It is safe to say that some form of 
remedial treatment has been found for every markedly injurious insect in the United 
States, but continued efforts are being made to find something more effective or 
cheaper o¢ simpler. 
_ Many striking things have been accomplished. The pear thrips, which at one time 
threatened the extinction of the Pacific coast deciduous-fruit industry, is no longer 
feared. Two serious pests of the clover-seed crop now can be handled by slight vari- 
ation of cropping wethods. The bark-beetles of our coniferous forests, which have 
‘imposed 4 loss comparable to that resulting from forest fires, can be controlled at 
very little expense. Sprays and spraying machinery have been developed which can be 
used successfully against practically all leaf-feeding species. The fumigation of 
‘nursery stock and of warehouses has been perfectsd. Such injurious species as the 
Onion thrips, the grape-borry moth, the alfalfa weevil, ths tobacco hornworm, and 
many others of recent prominence, can be controlled. The spread of the gipsy and 
rowni-tail moths through our Northern forests and orchards has been prevented. These 
Gnjurious insects not only have been kept in a comparatively emall territory, but are 
being reduced in number year after year by active scouting, spraying, banding, and 
See destruction, and through the aid of auweiias brought from Europe and Japan, 
Although the spread of the cotton boll weevil-which represents probably the most dif- 
ficult problem in insect control—has not been stopped, the investigations of the de- 
partment's entomologists have shown the Southern planter how to reduce greatly the 
Dotential damage and how to grow cotton in spite of the weevil. 
4 An important development in this practical entomological work of recent years 
fas been the establishment of 2 number of mcre or less temporary field laboratories, 
‘scattered over the country. Thus the expert workers are taken into the centers of 
Bctivity of the injurious species. Great stress is being laid on what may be termed 
the cultural method of insect control. The intimate life rovnd of the insect pest 
‘ studied in close connection with farming methods in order to ascertain whether by 
a. dation of cultural practice the insect damage can not be considcrably reduced, 
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lemedial work of this sort is extremely practical. Investigations have shown that 
lan many instances partial or nearly complete control can be gained by some change in 
farm management. This naturally is the best remedy, except possibly in the case of 
‘introduced pests, where control can be secured by the employment of parasites or 
st er natural enemies. 
