572 ANNUAL REPORT OF THE Off. Doc. 



necessary iu applying oils. There are several methods of pre- 

 paring the lime and sulphur washes. Salt is often added but it 

 must he remembered that the salt does not have any insecticidal 

 value and is used only to make the wash stick. One wash that 

 can be used without boiling is known as the lime-sulpliur-soda wash 

 given to-day by Colonel Fox. This, however, is not yet generally 

 accepted bj' careful experimenters even in the State of New Yoik, 

 where the wash originated, and in correspondence with dozens 

 of our most careful economic entomologists in different states I 

 have learned that the standard remedy which they are recommend- 

 ing, and which is being used with entire success and satisfaction, 

 is the boiled lime and sulphur washes. This means they must be 

 boiled by artificial heat which can be done either over a fire in an 

 open iron kettle, stirring occasionally, or better, by live steam driven 

 from engines or boilers through pipes and into barrels, tanks or 

 vats prepared for this purpose. There are two formuke for the 

 lime-sulphur washes; one is the Oregon wash, which calls for fifty 

 pound's each of lime, sulphur and salt and six pounds copper sul- 

 phate in fifty gallons of water; the other is the California wash, 

 as published in our November Bulletin, calling for thirty pounds 

 of unslaked lime, twenty pounds of sulphur and fifteen pounds 

 of salt for sixty gallons of water when completed. As is 

 said the salt may be omitted and it is probably as well to reduce 

 the lime to only thirty pounds. This should be boiled for two full 

 hours, at which time the mixture will assume an amber or reddish 

 color and the higher sulphur compounds, which are effective in 

 killing the insects, will have been formed. It must be strained 

 and applied while warm. The reason for applying it in this condition 

 is, that it runs better through the spraying apparatus and nozzles 

 and makes a better spra3^ Heat does not kill the insects; it is the 

 substance. It is desirable to make two applications; the second 

 may follow the first as soon as the latter is dried, but I consider 

 it better to make the first in the fall as soon as the leaves are off 

 and the second in the spring just before the buds burst. It will 

 not retain its insecticidal virtue for a great period and consequently 



m 



{■hould be used while fresh. Calcothon, which is a substance now 

 for sale by dealers, is practically this wash prepared and put into 

 barrels. It will be observed that the fall application does not re- 

 main on the branches nearly as long as the spring applications. 

 This is doubtless because the leaves, which appear soon after the 

 latter is made, protect the branches and keep the rains from wash- 

 ing the lime and sulphur away. It is important that one should 

 try and make these applications at a time when he will have a few 

 days dry weather following the spraying. It is not wholly effect- 

 ive if rain should come before the lime is dry, which is, of course, 

 within a few hours after having made the application. But it is 



