Bulletin 228] 



PEAR THRIPS AND PEACH TKEE UdUKU. 



371 



worked well. But it was necessary to enlarge slightly the opening in llio 

 disks of Vermorel type nozzles. We found it very important to have 

 the lime properly slaked. Good lime properly slaked is of creamy con- 

 sistency, with a negligible amount of grit. It forms a smooth, uniform, 

 creamy coating on the tree. An attempt to use improperly slaked limr 

 will usually result in complete failure. No amount of written inslruf 

 tion will teach one to slake lime. The laiowledge must come from actual 

 work with some one who has had the experience. 



In orchard practice we found it convenient to have our slaking vat, 

 which was 6 by 4 by 1 feet, elevated about three feet, with one end 

 slightly lower than the other. In the lower end we arranged a sliding 

 door through which the whitewash flowed by gravity into a containing 



(Unsprayed. ) (Whitewashed.) 



Fig. 4. — Fruit at harvest from treated and untreated trees. 



vat. The lower vat was shorter, narrower, and deeper than the slaking 

 vat to facilitate the removal of the material to the spray tank. Between 

 the two vats we arranged a piece of window screen, of one fourteenth 

 inch mesh, supported by chicken fencing, through which the whitewash 

 passed in flowing from the slaking vat. 



The cost of material ranges from one (1) to one and one half (1^) 

 cents per gallon, depending upon the cost of lime and labor. One 

 application proved sufficient to protect the blossoms and permit setting 

 of fruit. We did not find it necessary to spray a second time for larva\ 

 although in the first experiment enough larvje appeared to lead us to 

 believe that in some cases a second spraying would be necessary with 

 some good contact spray. 



