Summary of Bulletin No. 112. 



1. History of the cottony maple scale in Illinois, and especially recent 

 history in and about Chicago. Pag-e 343. 



2. Injurious effects of infestation of trees. Pag-e 345. 



3. Trees most likely to be injured are the soft maple, box-elder, and the 

 basswood. Other trees and shrubs liable to injury. Page 346. 



4. Life history of the insect. Single brooded. Males perish before win- 

 ter; females survive, partly grown, on twigs and smaller branches. Page 347. 



5. The hatching period is from June 15 to July 20; the beginning varies 

 as much as two weeks, according to latitude and weather. Page 349. 



6. Summer experiments with kerosene emulsion. One application of 

 10 per cent, emulsion, at middle of hatching period, killed about two thirds of 

 the scales, and two applications, at middle and end of hatching period, killed 

 about four fifths. Page 349. 



7. Winter insecticide measures more effective, a single treatment with 

 19 or 20 per cent, emulsion killing from 86 to 91 per cent, of the insects. 



Page 353. 



8. Diseased or weakened trees liable to serious injury by the kerosene 

 sprays. Page 355. 



9. Protection of roots against excess of insecticide suggested. 



Page 356. 



10. Successful use in Colorado of a winter spray containing only one 

 sixth of kerosene. Page 356. 



11. Insect enemies of the scale which have been found most effective for 

 its destruction. Page 357. 



12. Summary and general discussion. Page 358. 



