462 STATE BOARD OF AGRICULTURE. 



of the trees were not ?o crowded, and the fruit and foliage were thoroughly 

 covered with the spray mixture. In these instances the damage was noticeably 

 less than where the trees did not receive the late spraying. The dust spray 

 was again given a very thorough test on the Station orchards with practically the 

 same results as were obtained last year. Duplicate and comparative tests were 

 started in an apple orchard near the Station, but the fruit mostly dropped off, 

 after blossoming, and little in the way of definite results was obtained. 



With the appearance of San Jose scale in the orchards in different sections 

 of the fruit belt, it was thought best to secure the co-operation of interested 

 growers and carry on spraying experiments to determine the most satisfactory 

 way of controlling this insect. The experiments were started with special 

 reference to answering the many inquiries regarding the eflRciency of caustic 

 soda recommended by California parties as being cheaper and more effectual 

 than the lime, sulphur and salt wash which has been used to fight the scale. 

 The following parties kindly consented to co-operate in the experiment: Mr. 

 Fred Ruell. Kibbie, IMich.; M. F. Burgett, Berlamont, Mich.; Dr. F. B. Samson, 

 Benton Harbor, Mich.; and Mr. J. Hoppenroth, South Haven, Mich. The follow- 

 ing scheme for carrying out the work was sent to each party: 



Select fifty trees of medium size, upon which the scale is evenly distributed. 

 Thin out the heads, and cut back the branches somewhat more than in ordi- 

 nary pruning, in order to simplify the work of spraying. Divide the trees into 

 five plots of ten trees each, to afford equal conditions. Spray the trees with 

 the following materials: 



Plot 1. — Twenty-five pounds of lime, fifteen pounds of sulphur and eight 

 pounds of salt, prepared as follows: Place twelve gallons of water in a large 

 kettle and boil. Make a paste of the sulphur, and two gallons of the water 

 and add thisxahd twenty-five pounds of lime to the ten .gallons in the kettle. 

 Stir while it is slaking and boil for one hour; then add the salt and boil 

 fifteen minutes longer. Place in a barrel for spraying, and dilute to fifty gal- 

 lons, making the water warm enough to give the mixture a temperature of 

 about 120 degrees. 



Plot 2. — Use the same preparation as above, leaving out the salt. 



Plot 3. — Use the same material as in No. 1, (lime, sqlphur and salt) and 

 prepare as above without boiling after the lime is slaked, that is bring the 

 twelve gallons of water to a boiling point, and use as directed above, but rely 

 upon the heat generated in slaking the lime to cook the mixture. As soon as 

 the lime is slaked and the salt dissolved, place in a barrel, cover, and allow 

 to stand for an hour and a half, then dilute as above. 



Plot 4. — Prepare the sulphur and lime as for plot 3 and substitute six pounds 

 of caustic soda for eight pounds of salt; otherwise prepare and handle it as 

 in plot 3. 



Plot 5. — Dissolve six pounds of caustic soda and slake five pounds of lime. 

 Use in fifty gallons of water. 



The spraying was done in the early part of April. The conditions for carry- 

 ing out the experiments were as nearly equal as could be found and as the 

 results were nearly identical in all instances, it would indicate that the work 

 was thoroughly done. The sprayed orchards were examined July 14th to 16th. 

 The conclusions were as follows: 



It is time and money thrown away to use caustic soda at the rate of five 

 pounds to fifty gallons of water to control the San Jose scale, and to use 

 it stronger is dangerous to man and beast. Thousands of living scale were 

 found upon the trees treated with the above formula, while upon the trees 

 sprayed with the other formulas, the scale could not be found. There was 

 no difference in the different methods. It is evident from the results of these 

 experiments that it is the combination of lime and sulphur that destroys the 

 scale, and that the addition of copper sulphate, caustic soda and other materials 

 is an added expense and brings no better re.sults. 



To what extent the boiling and the length of time the mixture is boiled, 

 enter into the destructiveness of this wash, we do not know, except that the 

 boiling caused by the slaking of the lime, as used upon plot 3, gave the same 

 results as in plot 1, which was cooked for one hour. With the large amount 

 of spraying which will be necessary to control this insect in the future, it Is 

 highly important that a remedy be found that will be effectual and at the 

 same time easy to prepare and apply. Lime, sulphur and salt, using twenty- 



