224 FRUIT INSECTS 



is done in the bud itself; on prunes and peaches the nymphs 

 feed on the skin of the young fruits beneath the drying caUces, 

 causing scabby or silvered areas. On both prunes and cherries 

 much injury is caused by the egg-laying punctures in the fruit 

 stems ; the fruits turn yellow and drop. On all fruits the injury 

 to the foliage through a number of successive years tends to 

 weaken the trees and render them subject to disease. 



Remedial measures. 



The pear thrips may be satisfactorily controlled by proper 

 cultivation and spraying. During October, November and 

 December the ground should be plowed to a depth of 7 to 10 

 inches, harrowed, cross-plowed and again harrowed. This is 

 intended to break open the cells and kill the tender last stage 

 nymphs. This method has given good results in California 

 prune orchards, but is less efficient in pear orchards. 



Two sprayings should be made, the first just as the first buds 

 begin to open and the second just after the petals fall, using f 

 pint '^ Black Leaf 40 " tobacco extract in 100 gallons of water, 

 adding 5 pounds of soap. In the first spraying the object 

 is to force the liquid into the opening buds where it will kill the 

 thrips by contact. To do this it is necessary to use high pres- 

 sure, at least 150 pounds, and a rather coarse nozzle, spraying 

 down directly into the bud tips. In cases of severe infestation 

 it is sometimes advisable to make an additional application 

 directly after the first. Experiments in California have shown 

 that the thrips can be satisfactorily controlled by thoroughly 

 spraying the trees with a thick whitewash just as the buds 

 are opening. The whitewash is made by slaking 80 pounds 

 of quicklime for each 100 gallons of the wash. It should be 



strained before using. 



References 



U. S. Bur. Ent. Bull. 68, Pt. I. 1909. 



U. S. Bur. Ent. Bull. 80, Pt. IV. 1909. 



N. Y. (Geneva) Agr. Exp. Sta. Bull. 343. 1912. 



Cal. Agr. Exp. Sta. Bull. 228. 1912. 



