56 



CIRCULAR 2 7 0, U. S. DEPARTMENT OF AGRICULTURE 



It is being used very ex- 

 tensively in the East and to 

 a limited extent in the 

 Northwest. Detailed in- 

 formation on it may be 

 obtained by writing to the 

 Agricultural Experiment 

 Station of the State in 

 which the orchard to be 

 treated is located or to the 

 United States Department 

 of Agriculture. 



Other Borers 



Flatheaded borers are 

 often found in the trunks of 

 prune trees, particularly in 

 trees not in the best condi- 

 tion. A darkened area of 

 bark is an indication that 

 the borers may be present. 

 The pear blight beetle is an- 

 other insect that attacks 

 unhealthy trees, making 

 round, shotlike holes in the 

 trunks. These pests are dis- 

 cussed on pages 35 and 36. 



Pear Thrips 



The pear thrips (Taenio- 

 thrips inconsequens (Uzel) 

 causes more injury to prune 

 trees in the Pacific North- 

 west than to pears or other 

 fruits. The insect occurs in 

 western and northeastern 

 Oregon, in southeastern 

 Washington, and in western 

 British Columbia. It has 

 apparently been introduced 

 from Europe. There are 

 three types of injury. The 

 most serious injury is caused 

 by the adult thrips, which 

 emerge from the ground in 

 Figure 63.— Prune twig showing deformed the spring, feed in the de- 

 leaves and poor set of fruit caused by the veloping buds, and produce 

 pear thrips. deformed leaves and blos- 



soms (fig. 63), thus causing a reduction of the crop. Later the adults 

 lay eggs in the stems of the fruit and foliage. Both the young and the 

 adultsfeed by rasping the surface and then sucking out the plant juices. 



