New York Agricultural Experiment Station. 209 



TREATMENT OF THE DISEASE ON BEARING PLUM 



TREES. 



The investigations in 1895 showed that while the treatment 

 with the eau celeste checked the disease it injured the foliage. 

 The treatment with Bordeaux mixture did just as much good, or 

 even more, in checking the disease, and it did not hurt the foliage. 

 There was no good chance to compare these two remedies in 

 August, either in 1895 or 1896, as the trees did not show enough 

 injury early in August to permit of a satisfactory comparison of 

 the two remedies. In the latter part of August and in September 

 and October the good effects of the early spraying which was 

 done in May and June showed very plainly. It seems probable 

 that if the early treatments are thoroughly made there will be 

 little need of spraying in August. Should August treatment be 

 found necessary eau celeste might be preferable because it is less 

 liable to show on the ripe fruit, but we are not prepared to say 

 that it is preferable. 



The Bordeaux mixture was so much superior to the eau celeste 

 in the trials which were made in 1895 that no experiments in 

 comparing the two mixtures for early treatment were made in 

 189G. 



The investigations as to the fewest number of treatments with 

 Bordeaux mixture, 1 to 11,* necessary to control the leaf spot on 

 bearing plum trees and the best time for making them, were con- 

 tinued in 1896 in the same orchard of T. C. Maxwell & Bros, 

 which was kindly offered to the Station for this purpose in 1895. 

 The treatn^ent gave marked results, especially with Italian prune, 

 and to a large extent confirmed the results of the work in 1895. 

 The weak Bordeaux mixture, 1 to 11, again proved entirely satis- 

 factory and it is confidently recommended for treating plum leaf 

 spot. 



Plan of the work in 1896. — Four series of treatments were 



compared, namely: 



Series 1. Italian Prune, Guii and Lombard were sprayed May 



14, June 3 and June 17. The first treatment^ May 14, was given 



soon after the blossoms fell. 



*The 1 to 11 formula for Bordeaux mixture requires one pound sulphate of copper to 

 make eleven gallons of the mixture. 



14 



