New York Agricultural Experiment Station. 451 



conditions for hiding places for the insects. Attention to the dis- 

 posal of such accumulations will greatly aid pear-growers in the 

 spraying for the " flies " especially, through the fewer opportunities 

 offered for the adults to secrete themselves from the sprays. 



The rough bark not only provides a shelter for the psyllas during 

 the winter but it also constitutes the chief obstacle to thorough 

 spraying during the dormant season to kill the hibernating " flies." 

 Its removal is desirable for two reasons: first, to render the trees less 

 attractive to the adults for the purposes of hibernation during late 

 fall, winter and early spring; and, second, to facilitate a more thorough 

 spraying of the trunks and lower portions of the larger limbs. The 

 loose bark should be removed by a dull hoe or floor scraper, preferably 

 during a wet period, as the bark is then more easily detached. Care 

 should be taken not to cut into the live tissues as the wounds may 

 become infected with disease. If many psyllas are hiding on the 

 trees the bark should be collected and burned to kill the insects 

 which are attached to the scrapings. 



ACKNOWLEDGMENTS. 



Acknowledgments are due to Hon. Calvin J. Huson, Com- 

 missioner of Agriculture, for the cooperation of the agents of the 

 State Bureau of Horticulture during the progress of the investiga- 

 tions; to Mr. L. F. Strickland, Horticultural Inspector in Niagara 

 county, and Mr. A. B. Buchholz, Horticultural Inspector in Orleans 

 county, for assistance in field operations; and to Collamer Bros., 

 and Mr. L. B. Wright, Hilton; Mr. Dewane Bogue, Medina; E. 

 Moody and Sons, and R. B. Oliver, Lockport; to Miss Mattie 

 Middlewood, Geneva; and to many other growers who permitted 

 the use of their orchards and assisted in various ways to further 

 the experiments. 



