EXPERIMENTS ON THE APPLE WITH SOME NEW FUNGICIDES. 



any further color change on account of the dark color of the copper 

 sulphid. This mixture is somewhat parallel in a general way as a 

 summer spray with the Oregon wash (so called) as a winter spray. 



The Oregon wash is made by adding bluestone solution to the 

 strong home-boiled lime-sulphur mixture and is used only for a 

 winter wash. It is more nearly like the copper-sulphid mixture tried 

 by W. H. Volck, County Entomologist, Watsonville, Cal., and de- 

 scribed in a report on powdery mildew of the apple. a The copper 

 sulphid used by Volck was made by adding bluestone to the commer- 

 cial lime-sulphur solution. This resulted in a strong mixture which 

 could not be used at once but, according to Mr. Volck, on decanting 

 and washing, it could be sprayed on the apple trees. The washing, 

 however, required two or three days. 



The new feature in making the copper-sulphid mixture is the use 

 of the self-boiled lime-sulphur as a basis. This is so mild in its com- 

 position as to permit the immediate use of the mixture without 

 washing. 



Plat 8, copper-sulphid mixture, No. 2. — This is a copper-sulphid 

 mixture made by using the standard Bordeaux mixture (3-3-50) 

 as a basis and adding a gallon of the strong commercial lime-sulphur 

 stock solution diluted in 2 or 3 gallons of water after the bluestone 

 and lime have been combined. This is also a mixture somewhat 

 similar to that used by Volck, a but is different in that it has an excess 

 of lime, a part of which is combined with bluestone before add- 

 ing the sulphur. On account of wanting to use this mixture at once 

 without washing and being afraid of its caustic action, only 1 gallon 

 of the lime-sulphur solution per 50 gallons was used, though 1| 

 gallons can be used in water alone. The mixture gave the light 

 reddish brown color characteristic of the copper sulphid. It was 

 applied without washing or decanting. 



Plat 9, iron-sulphid mixture. — The new form of iron-sulphid mix- 

 ture is made by using the self-boiled lime-sulphur (10-10-50) as a 

 basis. A barrel of the self-boiled lime-sulphur is prepared as already 

 described and diluted to about 40 gallons. Iron sulphate (copperas), 

 3 pounds, dissolved in 6 to 8 gallons of water, is then added. The 

 iron sulphate might perhaps be still further diluted to advantage. 

 When this is added and stirred into the barrel the mixture turns 

 inky black. Then 2 pounds of arsenate of lead are added, as before. 



The iron sulphate can be weighed out and dissolved in a large 

 bucket by stirring, or, better, it can be prepared in a stock solution, 



a ' ; The Apple Powdery Mildew in the Pajaro Valley," Special Bulletin No. 1, by 

 W. H. Volck, County Entomologist for Monterey and Santa Cruz counties. Watson- 

 ville, Cal., May, 1909. 

 [Cir. 58] 



