Circular No. 131, 



Issued January 9, 1911. 



United States Department of Agriculture, 



BUREAU OF ENTOMOLOGY. 

 L. O. HOWARD, Entomologist and Chief of Bureau. 



HOW TO CONTROL THE PEAR THRIPS.« 



(Euthrips pyri Daniel.) 



By S. W. Foster and P. II. Jones, 



Agents and Experts. 



DISTRIBUTION. 



The pear thrips (Euthrips pyri Daniel) (fig. 2) is at present confined 

 to California and is very destructive throughout Santa Clara, Contra 

 Costa, Solano, and Sacramento counties, with 

 considerable areas infested in Alameda, Yolo, 

 Napa, and Sonoma counties. (Fig. 1.) Re- 

 ports of the presence of this species in other sec- 

 tions of California and in Oregon have been re- 

 ceived, but each case was closely investigated 

 and the insect in question found to be some other 

 species. Bagnal'' reports this insect in 

 England; otherwise it is not known 

 outside the State of California. 



ECONOMIC IMPORTANCE. 



Fig. 1.— Map showing area infested by pear thrips in California. 

 (Original.) 



suddenness of attack in great numbers 



The pear thrips is at present tne 

 most important in- 

 sect pest with which 

 the growers of de- 

 ciduous fruits in the 

 counties mentioned 

 have to contend. 

 On account of the 

 minute size of the 

 insect, the rapidity 

 of its spread over 

 large areas, and the 

 completely blasting in a few 



« The present paper is an abstract of a more comprehensive report on the life history 

 and control of the pear thrips to be published later. The re<'ommendations friven are 

 based on the results of experiments carried out in the i)rincii)al centers of infestation 

 since the fall of 1908 to and including the summer of 1910. 



b Journal of Economic Biology, vol. 4, No. 2, 1909. 



