48 BULLETIN 395, V. S. DEPARTMENT OF AGRICULTURE. 



nate of lead, without serious injury to the host; and (3) that sulphur 

 paste may control this disease. 



The purposes of the writer's experiments were (1 ) to test further, in 

 relation to locahty, season, and variety, the excellent spray schedules 

 worked out by Scott and others; (2) to test the efficiency and desir- 

 ability of a sulphur spray in comparison with self -boiled lime-sidphur; 

 and (3) to correlate with control measures a clearer understanding of 

 the nature, cause, and development of the disease. 



The spraying experiments ^ were conducted in commercial orchards 

 at Corneha, Ga., in 1910, 1912, and 1913, and at Hart, Mich., in 1911. 

 More than 150 plats, containing over 10,000 trees, were sprayed, 

 while parallel observations were made upon commercial orchards 

 containing in the aggregate many hundred thousand trees. 



In the experiments of 1911, 1912, and 1913, the spray was appUed 

 by means of a gasoHne power sprayer, double "Friend" nozzles being 

 used. At Cornelia, in 1910, good barrel outfits were employed. 



Careful field observations of each plat were recorded throughout 

 the season. At harvest time, in as many cases as was feasible, the 

 fruit from a number of typical trees of each plat, usually 10 to 12, was 

 picked, critically examined, and classified according to the occurrence 

 and abundance of scab, the occurrence of brown-rot, and the salability 

 of the fruit. By carefully noting many thousands of fruits in this 

 fashion and tabulating the resulting data, it was possible to arrive 

 at strikingly accurate and concrete comparisons of the efficiency of 

 the different treatments. 



Experiments in 1910 and 1911. ^ 



The season of 1910 in northern Georgia was very favorable for the 

 development of scab and brown-rot and offered a severe test of the 

 efficiency of the various treatments used. The results were eminently 

 satisfactory, but since they have been reported in brief by Scott and 

 Quaintance (1911, p. 23-26), they will not be considered further here. 



In 1911 extensive experiments were conducted at Hart, Mich., 

 on 10 of the more important commercial varieties of that section. 

 Owing to an unusually dry spring and summer, so Httle scab occurred, 

 even upon unsprayed trees, that little differentiation of results of the 

 various treatments was feasible. Even under these conditions, how- 

 ever, the sprayed fruit appeared to be sufficiently superior to that of 

 the control plats to justify the expense of the treatments. These 

 residts wiU not be considered further in this connection. 



> Grateful acknowledgments are made to Messrs. A. M. Kitchen, Cornelia, Ga. (1910), H. W. Gebhart 

 and F. Brooker, Hart, Mich. (1911), A. B. Veeder, S. R. Christie, and Laing & Segers, Cornelia, Ga. (1912), 

 and W. B. Hunter, Cornelia, Ga. (1913), for their cordial cooperation. 



^ These experiments were conducted under the direction of Mr. W. M. Scott, formerly Pathologist, Office 

 of Fruit-Disease Investigations, Bureau of Plant Industry, U. S. Department of Agriculture. 



