120 STATE BOARD OF AGRICULTURE. 



leaf eating insects, it brings the cost of the dust applications nearly up 

 to that of the liquid sprays. In favor of the dust sprays may be urged 

 that they require less labor th'an the liquid applications, are better 

 adapted for use upon rough and uneven ground and especially in sec- 

 tions where water cannot be readily obtained. They are, however, gener- 

 ally quite satisfactory against the canker-worm, codling moth and other 

 leaf-eating insects, and the machinery in use today will make it possible 

 to rely upon dust sprays against the potato beetle. While less effectual 

 than liquid sprays against fungous diseases in the experiments made 

 up to the present time, it is possible that improvements in the formulas 

 or in the methods of compounding themi may increase their value against 

 the parasitic fungi. 



During the year a considerable number of experiments were taken 

 up in the vicinity of South Haven and Benton Harbor in cooperation 

 with numerous fruit growlers. The more important were concerned with 

 the testing of various mixtures for the destruction of the San Jos6 scale. 

 Up to the present time the most effectual preparation has been the sul- 

 phur, lime and salt, prepared after the California formula. During the 

 last year it has been used by hundreds of fruit gi'owers and where prop- 

 erly prepared and thoroughly applied, it has not only served to des- 

 troy the scale and other insects but it has proved very effectual against 

 apple-scab, leaf-curl and other fungous diseases. In many instances 

 trees that had through neglect become coated with rough bark and 

 lichens were after spraying with the sulphur, lime and salt mixture left 

 with a clean, healthy bark. A large number of fruit growers who were 

 obliged to spray their trees for the destruction of the scale, were so well 

 pleased with the results that they almost considered it a blessing that 

 their trees had become infested. 



The great drawback to the use of the California wash is that it re- 

 quires boiling for an hour or more and when one is not equipped with 

 the necessary apparatus it is a tedious job, especially if a large quan- 

 tity is required. However, by the use of a steam boiler or a stock feed- 

 cooker the work is greatly simplified and an outfit of this kind will 

 always be found desirable if a considerable number of trees are to be 

 sprayed. During the year, various methods of preparing this mixture 

 without actually cooking it have been recommended and it was thought 

 advisable to test them in order that their merits might be ascertained 

 and in case any of them proved effectual, it was hoped that the saving 

 of labor that would result might be of value to the hundreds of persons 

 in Michigan who have a few infested trees. One of the methods tested 

 made use of the heat produced by the slaking of the lime for boiling the 

 mixture. Another introduced caustic soda without an}' attention to boil- 

 ing. Another remedy which has been highly recommended by a lead- 

 ing agricultural paper, is a solution of caustic soda and, although little 

 was expected from it, it was thoroughly tested upon several orchards. 

 While it is not possible to give definite results, the indications at this 

 time are that none of the preparations are as effectual as the thoroughly 

 cooked sulphur, lime and salt, and that the benefits derived from the 

 caustic soda solution are the least marked of all. The San Jos6 scale 

 multiplies so rapidly that even though only a few per cent of the insects 

 survive the treatment, the number upon a tree after one brood has de- 

 veloped may be gTeater than before the trees were sprayed, while after 



