259 ANNUAL REPORT OF THE Off. Doc. 



whitewash which may remain intact a long time. In Central and 

 Southern California, indeed throughout most of that State, long 

 periods of dry weather give opportunity for the mixture to produce 

 its maximum effect. In the moist climate of the Atlantic slope, the 

 dry winter periods sufficient to allow the insecticide to act, are ex- 

 ceptional and their occurrence cannot be foretold. 



A complete analysis of this material and a technical statement of 

 just what chemical changes occur, is to be found in Bulletin No. 30, 

 New Series, of the Division of Entomology of the U. S. Department 

 of Agriculture. What has been said in the previous jiaragraph pre- 

 sents the result in a generalized form. 



It is fair to state that in Oregon w^here rains are frequent, the 

 wash is as successfully used as in California, with a different formula 

 for its make-up. It is also well to say that in the winter of 1900-'01 

 the Oregon formula was satisfactorily used in Burlington couaty, 

 New Jersey, while one of the Californian mixtures was successful in 

 Washington, D. C. Mr. Marlatt had in previous years used the wash 

 in Washington, fully as well made and applied under favorable con- 

 ditions, always without satisfactory results. He attributes the suc- 

 cess of 1900-'01 to a period of dry weather, lasting three weeks after 

 the application was made. The New Jersey result cannot be explained 

 in this way, for rain began before the treatment was completed. Inas- 

 much as in another State the same wash had been an almost absolute 

 failure, we are left somewhat at sea as to the actual value of the 

 material under Pennsylvania conditions. Applications will be made 

 in New Jersey during the present winter under careful supervision 

 on a scale large enough to determine the practical worth of thfr 

 mixture in the East.* 



Inasmuch as the wash is absolutely safe on peach trees, the import- 

 ance of a thorough trial is obvious and as some benefit is almost cer- 

 tain to be derived, it may pay Pennsylvania peach growers to give it 

 a trial. 



The Oregon formula which was used in New Jersey, is as follows: 



Sulphur, ground (pounds), 50 



Lime, unslacked (pounds), 50 



Salt, stock (pounds), 50 



This will make 150 gallons of wash. 



Slack the fifty pounds of lime in enough water to do it thoroughly, 

 add the fifty pounds of sulphur and boil briskly for at least an hour, 

 adding water in small quantities as necessary; then add the salt 

 and boil hard for at least fifteen minutes more. Add hot water to 

 make the 150 gallons and apply at a temperature of at least 100 de- 

 grees. Strain before using and apply with a Bordeaux or similar 

 coarse nozzle. 



•Since the above was written a year has passed. The wash has been extensively used and with 

 almost uniformly g'ood results. It has become the standard insecticide for this scale In some 

 localities and is unreservedly recommended as best for peach trees. 



