BULLETIN No. 214. 



DEPARTMENT OF BOTANY. 



COMBATING APPLE SCAB. 

 SPRAYING AND DUSTING EXPERIMENTS IN 1922.^ 



BY WEBSTER S. KROUT, 



Introduction. 



The fact of control by both spraying and dusting is outstanding at the 

 end of the second year's field study of this fungous disease. Weather 

 conditions in both 1921 and 1922 were most adverse to successful spraying 

 and dusting, and most favorable to scab infection, yet despite these 

 handicaps almost perfect control was obtained. 



These investigations were started in the fall of 1920. In the fall of 

 1921 a report of the results of the first year's work was published through 

 the Extension Service of the College in a pamphlet entitled "Apple Scab 

 and its Control." This bulletin presents to the practical orchardist a 

 similar report for 1922. 



The field work has been conducted in three orchards under the direct 

 supervision of the writer. In three other orchards he was present when- 

 ever possible. The spraying experiments Avere in the orchards of Stephen 

 Sabine of Groton and Harr}^ L. Knights and H. L. Frost of Littleton. 

 The dusting experiments were conducted in the orchards of Harry L. 

 Knights and H. L. Frost of Littleton, A. N. Stowe of Hudson, George A. 

 Marshall of Fitchburg and R. J. Fiske of Lunenburg. Especially helpful 

 was the co-operation of J. W. Ames, superintendent of the Knights farm, 

 Roy C. Wilbur, superintendent of the Frost farm, John J. Collins, super- 

 intendent of the Stowe farm, and the officers of the Nashoba Fruit Pro- 

 ducers Association. 



> The writer is indebted to Prof. A. Vincent Osmun, head of the Department of Botany of 

 the Massachusetts Agricultural Experiment Station, for many helpful suggestions during the 

 progress of this study. 



