No. 6. DEPARTMENT OF AGRICULTURE. 581 



to become fixed and secrete coverings much sooner than when the 

 trees were not treated. When applied strong enough to kill the 

 adult scale the foliage was badly burned, and in some cases the 

 trees were killed. 



From these experiments we found to make Summer Spraying 

 successful in the slightest degree we had to spray at least once a 

 week during the entire breeding season. Orr best results were 

 obtained by using Whale Oil Soap, 1 pound in 5 gallons of water, 

 which killed a large number of the crawling young, and no harm 

 could be noticed to the tree on which it was applied. 



To determine the real value of some of the most widely advertised 

 commercial insecticides, a series of experiments was started early 

 last autumn, and this has been continued up to the present time. 

 Although it is impossible to give the final results of these experi- 

 ments at present, yet we can now give the results of the trees 

 sprayed prior to December 20, 1905, working on the basis that an 

 insecticide exerts all its influence within a month from the time of 

 application. 



Thirty trees, consisting of apple, peach, pear and cherry were 

 sprayed December 6, 1905, with "Horicum," which is a prepared 

 form of the Lime-sulphur-salt mixture, made and sold by the Ham- 

 mond Slug Shot Works, at fifty cents per gallon when purchased 

 in 50-gal. lots. This was applied in proportion of one part to twenty- 

 five parts of water. One application was made with a result that 

 from fifty-five to sixty-five per cent, of the San Jose" Scale were dead 

 on January 25. 



"Target Brand Scale Destroyer," made by the Horticultural Dis 

 tributing Company, was applied in proportion of one part to twenty- 

 five parts of water on one hundred trees, consisting of apple, plum 

 and a few peach. The result here was very poor, as with the pre- 

 ceding, as not more than fifty or sixty per cent, of the insects were 

 killed. The results were about the same on all varieties of trees. 

 The material was applied December 6, and the last examination was 

 January 5. 



"Target Brand Resin Emulsion," made by the same firm as the 

 above, was sprayed on a few trees but owing to a tendency to gum 

 both pump and nozzle it was very difficult to apply. On both the 

 peach and plum trees the results were far from satisfactory. This 

 was applied October 10, and the last examination on January 10, 

 showed not more than fifty per cent. dead. The young larvre con- 

 tinued to fix and secrete a coating for some weeks after this ma- 

 terial was applied thoroughly to the trees infeste*d with them. 



"Kill-O-Scale," made by the Thompson Chemical Company, was 

 applied Dec. 8, one part to twenty parts of water, on about fifty 

 plum and pear trees moderately infested. The results here varied 

 considerably, but the average showed not more than fifty to sixty 

 per cent, of the scale dead on Jan. 5. A second application on 

 the same varieties of trees December 19, gave the same results. 

 These results together with the high price of the insecticide i-fl.00 

 per gallon when purchased in large quantities) would certainly con- 

 demn its use in comparison with the more successful and cheaper 

 remedies, such as Lime-sulphur wash or Whale Oil Soap. 



Warren's "O. K.," made and sold by S. R. Warren, was applied 

 one part to twenty of water on twenty-five apple and plum trees, 



