THK PEAR THRIPS. 17 



We believe that if the ground be thoroughly plowed and cultivated 

 during November, December, and January, or before the insects leave 

 the ground, which they begin to do by the first of February, many of 

 these young thrips would be killed or injured or so disturbed that but 

 few would ever reach maturity. 



Our present manner of cultivation is well adapted to give the thrips 

 a long, undisturbed period of rest. During the late spring and early 

 summer, when thrips are in the ground, we give the soil nothing but 

 light cultivation, and as the insects are still in an active larval stage they 

 seek another place of hiding, if disturbed. After this no cultivation is 

 usually done until the last of February or March of the following year, 

 by which time the insects have left the ground. While the plowing 

 and cultivating method of control has not been thoroughly tried, we 

 believe it gives more promise than any other yet suggested. 



SUMMARY. 



The insect is single-brooded. Adult females appear and begin to 

 deposit eggs in February. After four days in the egg the young appear, 

 feed for a time on the tree, then drop and enter the ground, where the 

 greater part of the year is passed. 



No effective natural enemies are yet known. 



Owing to the insect's method of feeding, its habits of coming from the 

 ground, extending over a period of several weeks, and its habits of 

 migrating, sprays can be only partially effective, even where thoroughly 

 ! applied. 



We suggest winter plowing and cultivating, with careful working 

 ; about the trees, so as to kill or injure the immature forms of thrips. 

 iThis plowing must be done before the first of February, at which time 

 the mature insects begin to come out from the ground. 



