INSECTS INJURIOUS TO ORCHARD TREES 433 



an irregular nest in which the larvae of the bud-moth feed and 

 in which they pupate. Because they attack the buds before 

 they are open they are able to do considerable damage before 

 anything can be done to control them. 



A careful spraying with arsenate of lead just as the leaves 

 begin to unfold is about the only remedy that can be recom- 

 mended. 



The Pear Thrips (Euthrips pyri). For several years this 

 little insect has been the most serious pest with which the 

 orchardists of central California have had to contend, and 

 recently it has been discovered 

 that it also occurs in some of 

 the eastern states where it does 

 considerable damage. It at- 

 tacks many kinds of orchard 

 trees, but does particular injury 

 to pears, cherries and prunes. 

 The adult thrips are minute, 

 black-bodied insects with their 

 four long narrow wings fringed 

 with long hairs. They appear 

 early in the spring and soon 

 make their way into the ten- 

 derest part of the bud, often 

 completely destroying it. A 

 little later they begin laying the eggs from which the wingless 

 young thrips hatch. These continue the destructive work 

 begun by the adults. The insect passes the winter in the 

 larval and pupal stages in the ground, the adult issuing very 

 early the following spring. 



In fighting this pest some insecticide must be used that will 

 penetrate the buds and kill the thrips without injuring the 

 buds. The distillate oil emulsion and tobacco extract (see 

 page 417) have proved most efficient in California. The first 

 spraying must be done as soon as the adult thrips are numerous 

 on the trees, the second application should follow ten days 

 later, and still a third, which is for the larvae, should be given 

 about two weeks after the second. Deep plowing in the fall 

 28 



FIG. 206. The pear thrips, adult- 

 (Much enlarged; after Moulton.) 



