New York Agricultural Experiment Station. 319 



PLAN AND CONDITIONS OF THE EXPERIMENT. 



Plan. 



In any orchard the amount of injury from scab is liable to vary 

 considerably with different trees of the same variety in the same 

 season. It may also vary greatly with the same tree in different 

 seasons, being influenced by the conditions of light, tem- 

 perature and moisture. The investigation was planned on an 

 extensive scale, so that the peculiar environment of individual 

 trees and the varying influences of different seasons might not 

 lead to erroneous conclusions. Some sections of the orchard in 

 which the experiment was conducted were annually fertilized 

 with liberal applications of wood ashes and corresponding sec- 

 tions received no ashes. As many trees of a kind as possible 

 were included in each of the two classes, the treated and 

 the untreated, and the experiment has continued five years. For- 

 tunately for the experiment, the scab was unusually abundant 

 one season, 1894, and did an enormous amount of injury to apple 

 foliage and fruit throughout the State. The period of the experi- 

 ment also covers the seasons of 1895 and 1896 in which the cli- 

 matic conditions were generally favorable to the production of 

 foliage and fruit free from the scab. 



To guard against the possibility of having the test ruined by 

 insects, the orchard was sprayed each year with arsenites and the 

 insects were thus kept under control, excepting plant lice. No 

 fungicides were used.* Since all sections were treated alike the 

 spraying did not lessen the value of the records for comparing 

 sections which were treated with ashes with corresponding un- 

 treated sections. The trees were annually pruned for the pur- 

 pose of removing weak or dead branches and ke-eping the tops 

 open so that spraying could be done readily. The fruit was not 

 thinned, because more scabby fruit might thus be taken from 

 treated than from untreated sections or vice versa. 



♦The insecticides wtiicli were used were London purple, Scheele's green and Paris 

 green. Lodeman lias shown that Paris green has slight fungicidal value. Cornell Exp. 

 Sta. Bull. 48, pp. 272-273. In his tests London purple showed no fungicidal value. Cor- 

 nell Exp. Sta. Bull. 86, p. 60. 



