BULLETIN OF THE 



i) 



No. 173 



Contribution from the Bureau of Entomology, L. O, Howard, Chief. 

 April 13, 1915. 



(PROFESSIONAL PAPER.) 



THE LIFE HISTORY AND HABITS OF THE PEAR 

 THRIPS IN CALIFORNIA. 



By S. W. Foster x and P. R. Jones, 2 Entomological Assistants, Deciduous Fruit 



Insect Investigations. 



INTRODUCTION. 3 



The so-called pear thrips, (Euthrips) Ts&niothrips pyri Daniel, first 

 attracted attention during the spring of 1902 in a prune orchard 

 near San Jose, Cal. Its injuries rapidly increased in the Santa 

 Clara Valley, and the insect spread to other orchard sections in the 

 San Francisco Bay region. Its increasing destructiveness and 

 spread led to the establishment by the Bureau of Entomology of a 

 laboratory in the Santa Clara Valley to determine the life history 

 and habits of the pest and to determine, if possible, measures for its 

 control in orchards. The laboratory thus started during the summer 

 of 1907 was continued to the fall of 1912. 



Mr. Dudley Moulton, an agent of this bureau, who, as Santa Clara 

 County entomologist, had previously had experience with the insect, 

 was placed in immediate charge of the work, in which position he 

 continued until September, 1909. During his period of service 

 Mr. Moulton was assisted in the Santa Clara Valley at one time or 

 another by Messrs. C. T. Paine, S. W. Foster, and P. R. Jones. 



In the fall of 1908 owing to the rapid dissemination of the pear 

 thrips to the northward an additional laboratory was established in 

 Contra Costa County, with headquarters at Walnut Creek. This 

 work was placed under the immediate direction of Mr. S. W. Foster, 

 who also had charge of operations in the infested counties to the north. 

 During the spraying season of 1909 Mr. Fred Johnson collaborated 

 with Mr. Foster in experimental and demonstration spraying in 



i Resigned Oct. 10, 1912. 



2 Resigned Sept. 30, 1912. 



3 By A. L. Quaintance, In Charge of Deciduous Fruit Insect Investigations. 

 73390°— Bull. 173—15 1 



