SPRAYING 109 



In the last few years one of our native scales 

 has been causing considerable trouble among 

 fruit-growers. This is the oyster shell scale, so 

 called from the shape of the scale covering 

 which it secretes. Formerly but little atten- 

 tion was paid to this pest because it seemed to 

 limit its attacks to only a few shrubs and to 

 be more or less perfectly controlled by native 

 parasites. In the last five years, however, it 

 has become a real factor in orchard work in 

 several sections. I have seen apple trees killed 

 by it in northern Michigan, and Mr. Frank N. 

 Wallace, State Entomologist of Indiana, re- 

 ports that his inspectors are finding it more 

 and more frequently in their orchard inspec- 

 tions. It is a larger and more conspicuous scale 

 than its Chinese relative and its life-history is 

 different in that it passes the winter in the egg 

 stage rather than as an immature female. These 

 eggs are deposited by the female late in the 

 fall, under the scale cover which has been her 

 own protection during her lifetime. Conse- 

 quently the insect is doubly protected — by the 

 scale and by the tough egg-shell — thus mak- 

 ing it particularly hard to kill with ordinary 

 spray solutions. 



The scurfy scale, another native, also passes 

 the winter in the egg stage much as does the 

 oyster shell, but it seldom becomes an impor- 

 tant factor in the orchard. 



