EXPERIMENTS ON THE APPLE WITH SOME NEW FUNGICIDES. 9 



as is customary with copper sulphate, at the rate of 1 pound to the 

 gallon of water. 



The new feature in this iron sulphid, as in the new copper sulphid, 

 consists in using the self-boiled lime-sulphur as a basis instead of the 

 concentrated lime-sulphur solution. Volck, in the bulletin already 

 cited, described an iron sulphid like his copper sulphid, made by 

 adding iron sulphate to the lime-sulphur solution. But this, like the 

 copper sulphid, required decanting and washing for two or three days 

 to render it suitable for use upon foliage. It was decided to use the 

 self-boiled lime-sulphur in the hope of getting a more harmless mixture 

 which could be made up and used at once, as the washing was not 

 considered practicable or was, at least, very objectionable. The plan 

 succeeded in that the mixture was quite harmless. The inky black 

 mixture was apparently colloidal or somewhat gelatinous in texture 

 and after drying on the trees turned a dark slate color. In a few 

 days this oxidized to a reddish brown color, which remained constant. 



RESULTS. 



Apple leaf-spot and the cedar-rust fungus began to appear on the 

 leaves of the unsprayed trees at the date of the second treatment. 

 Furthermore, a rather vicious spray injury of the foliage and rus- 

 seting of the fruit began to appear on the Bordeaux-mixture plats 

 at the same time. The taking of notes of the results was begun, 

 therefore, at that time and continued at frequent intervals through- 

 out the season. The fruit was sorted and weighed at picking time 

 and a sample box of apples from each important plat was packed 

 and placed in cold storage. Careful notes on the condition of the 

 fruit from the different plats were taken at picking time and again 

 at the time the fruit was removed from cold storage, when it was 

 placed on exhibition before the Virginia State Horticultural Society, 

 January 5 to 7. The details as to the differences between these 

 plats and between the resulting fruits may be described more fully 

 in a later publication. For the present purpose, however, the fol- 

 lowing important results may be stated: 



SERIES I. 



All the fungicides protected the trees almost completely from 

 fungous diseases, and since the arsenate of lead was combined with 

 them they also controlled the codling moth and other insect pests. 

 It therefore became a question, as was intended from the start, of 

 determining the merits of the different mixtures largely through 

 their effect in producing spray injury. 

 37294°— Cir. 58—10^2 



