New York Agricultural Experiment Station. 365 



The period for effective spraying against the adult or winged 

 thrips is during the time when the buds are swollen and partly 

 open and until they are entirely opened at the tips. The first 

 treatment should be made as soon as the thrips become numerous 

 on the trees. The number of the applications required will de- 

 pend on the thoroughness of the treatments. The grower should 

 spray on successive days or every few days until the thrips are 

 reduced to comparatively few individuals. Two, or certainly not 

 more than three, sprayings are required to afford efficient protec- 

 tion to the trees from the adult thrips. Especially hard to kill 

 are the insects within the buds, as they are often hidden ; and it i=5 

 difficult to force the spraying mixture in between the growing 

 structures of the bud. "While it is not possible to reach all of 

 these, many of them may be destroyed by careful work in apply- 

 ing the sprays. By successive applications important injuries 

 may be largely or entirely prevented. To derive the greatest 

 benefits from the treatments, apply the spraying mixtures in lib- 

 eral quantities as a rather coarse driving spray, holding the nozzle 

 fairly close to the buds in order to force the liquid into the ends 

 of the buds. The " angle nozzles " of the large chamber type or 

 nozzles set on an angle to the extension rod, maintaining a press- 

 ure of not less than one hundred fifty pounds are preferable for 

 this purpose. 



The larvae may be seen in large numbers as small, whitish crea- 

 tures in the calyx cups ; and on pears especially they are much ex- 

 posed to spraying because of the open nature of the blossom ends 

 of the young fruits. One or two careful sprayings will practically 

 free the trees of the insects. In making an application both sur- 

 faces of the leaves and the calyx ends of the young fruit should 

 be thoroughly wetted by the liquid. Spraying for the larvae is 

 important because it will greatly reduce the numbers of the insects 

 which seek shelter in the ground until the following spring. The 

 accumulative benefits from the destruction of the larvgs for suc- 

 cessive years, while not as yet definitely known, must be consid- 

 erable. 



