2 BULLETIN 173, U. S. DEPARTMENT OF AGRICULTURE. 



orchards, and in July of the same year Mr. E. J. Hoddy was assigned 

 to the Walnut Creek laboratory and assisted in certain cultivation 

 experiments at Suisun in the fall of 1909, and with Mr. R. W. Braucher 

 assisted hi the demonstration spraying operations at Suisun and 

 Courtland during the spring of 1910. During the spraying season 

 of 1911 Mr. Foster was assisted by Messrs. E. L. Jenne and R. L. 

 Nougaret. 



Upon the resignation of Mr. Dudley Moulton Mr. P. R. Jones was 

 placed hi charge of operations in the Santa Clara Valley and was 

 assisted during the spraying season of 1910 by Mr. E. L. Jenne and 

 during the spraying season of 1911 by Messrs. A. G. Hammar and 

 W. M. Davidson. 



During the spraying season of 1912, owing to the absence from 

 California of Mr. Foster, Mr. Jones was charged with all of the pear- 

 thrips operations in California and was assisted in the work by Messrs. 

 W. M. Davidson and L. L. Scott, located at Courtland, by Mr. R. L. 

 Nougaret at Suisun, and by Mr. E. L. Jenne at Walnut Creek. 



The manuscript for the present report has been prepared as fol- 

 lows: All of the data relating to Contra Costa County and counties 

 to the northward have been prepared by Mr. Foster, the senior author. 

 Report of operations in the Santa Clara Valley, as well as much of 

 the life-history matter, has been prepared by Mr. Jones. The re- 

 maining chapters were written jointly by Messrs. Foster and Jones. 



Especial acknowledgment is due to the supervisors of Contra Costa 

 County and Santa Clara County for their assistance in furnishing 

 facilities for work during the season of 1909, and for supplementing 

 the bureau's funds before the special appropriation from Congress 

 was available. The bureau desires also to acknowledge its obliga- 

 tions to many orchardists in the thrips-infested territory, who placed 

 at the disposal of the Department of Agriculture their orchards and 

 facilities for experimental and demonstration purposes. The suc- 

 cess which many orchardists have obtained in the control of the 

 pear thrips by the adoption of the recommendations of the bureau, 

 as well as the large-scale spraying demonstrations which the bureau 

 has conducted, has fully demonstrated the effectiveness and practi- 

 cability of the methods recommended. Especial acknowledgment 

 is made also to Mr. W. S. Ballard, of the Bureau of Plant Industry of 

 the United States Department of Agriculture, for much valuable 

 assistance and numerous courtesies rendered during the course of 

 the work at Suisun. 



The present paper deals with the life history and habits of the 

 pear thrips, the results of experiments and demonstrations with 

 sprays and other remedial operations having been given in Circular 

 No. 131 of the Bureau of Entomology. 



