THE LIME-SULFUR WASH. 73 



with the uncertainty of composition. Nevertheless, where only a few 

 trees are to be sprayed and the owners would probably not go to the 

 trouble of preparing a standard emulsion or the lime-sulfur wash, the 

 use of miscible oils or readj^-made lime-sulfur washes is a good deal 

 better than nothing, and ma}^ give very good results. Space does not 

 permit the mention and discussion of a number of other mixtures which 

 have not proven satisfactory^ nor the equal of standard means of 

 control. Some of these have been experimented with somewhat 

 extensively b}^ different experiment station entomologists. . 



The methods of control which have been especially followed in the 

 Eastern States are (1) the lime-sulfur wash, (2) the soap treatment, 

 (3) treatment with pure kerosene, (4) treatment with crude petroleum, 

 (5) treatment with mechanical mixtures of either of the last two oils 

 with water, and (6) petroleum emulsion with soap. All of these 

 methods have proved themselves to be successful against the San Jose 

 scale when properly carried out. As compared with the lime-sulfur 

 wash, the others mentioned are more expensive, and the two oils, 

 unless very carefulh^ applied, are likely to injure the treated plants 

 and are now seldom used. One's choice of method must therefore be 

 governed by availability^ special needs, and experience. In the main 

 these remedies, including the lime-sulfur wash, are winter treatments 

 and ma}'- be employed at any time when the trees are in dormant, leaf- 

 less condition. The weaker oil-water mixtures and the emulsions may, 

 however, be used in the growing season. The treatments enumerated 

 are all for trees in the orchard. Nursery stock badly enough infested 

 to require such treatment is best destroyed. For the general disinfec- 

 tion of nurser}^ stock the hydrocyanic-acid-gas treatment is the standard 

 and only satisf actor}" means. 



THE LIME-SULFUK WASH. 



In California, where this scale insect first occur^red, the standard 

 remedy for it is the lime, sulfur, and salt wash, a mixture formerly 

 used as a sheep dip in Australia and employed with little change against 

 the San Jose scale, and by a lucky chance proving effective. This 

 wash was naturall}^ first thought of on the discovery of the San Jose 

 scale in eastern orchards. The earlier tests, however, conducted by 

 this office in 189J:, were unfavorable, and the experimentation which 

 . followed resulted in the demonstration by ourselves and others of sev- 

 eral distinct and valuable methods of control noted below. Later 

 studies of the action of this wash in California led the writer in 1900 

 to give it a farther careful trial in the East, with most successful 

 results, demonstrating that with favoring conditions, i. e., absence of 

 dashing rains for a few days subsequent to the application, it would 

 give just as good results in the Eastern States as on the Pacific coast. 



