132 



PEACH LEAF CURL: ITS NATURE AND TREATMENT. 

 Table 36. — Experiment No. 9, conducted by Mr. Smith Hawley. 



The preceding experiment shows that Mr. Hawley obtained from 

 his Hills Chile trees a net gain in fruit of 354 per cent by spraying 

 with the Bordeaux mixture (formula (J), and a net gain of 328 per 

 cent with the stronger sulphur spray when applied on April 12 and 

 200 per cent when applied on January 19. These results indicate that 

 the early winter treatment will probably not prove as effective in 

 Michigan as a treatment of the trees shortly before the buds swell in 

 the spring. It is probable, however, that the copper sprays will act 

 more quickly than the sulphur sprays, on which account the latter 

 should be allowed somewhat more time for action than the copper 

 sprays, by applying them a little earlier in the spring. The copper 

 sprays may be applied until the first buds begin to open, if neces- 

 sary, but such a late application of the sulphur sprays would endanger 

 the buds and new growth. 



The following are Mr. Hawley's notes on this experiment : 



Experiment 9: 



June 23, 1894. — This experiment, although on a small scale, has been very inter- 

 sting and instructive, and has been noted and admired by all who saw it. The 

 rees stand on a slope, and a person standing on the opposite slope, only a few rods 

 away, can see every tree, and the best possible chance is had to observe the effect of 

 the different sprays, and to compare the treated with the untreated trees. The con- 

 trast at this time is very remarkable. The trees were quite badly affected by leaf 

 curl last year. 



October 1, 1894.— The contrast between the treated and untreated trees is very 

 great as regards yield of fruit, and the contrast in the trees themselves at this date is 

 quite as remarkable. The treated trees look fresh and healthy and have made a fin_e 

 growth, while the mitreated trees look sickly and have made very little growth, 

 looking, in fact, a year or two younger, as regards size, than the others. 



Late in the season of 1894 Mr. Hawley tested the sulphur and copper 

 sprays to ascertain the comparative action of the same upon l)uds 

 which were considerably swollen. He learned that the sulphur spray 

 injured the buds to such an extent as to reduce the yield, while it 

 prevented curl. The copper spray, however, prevented curl and gave 

 a decided increase in yield. He thus reaches the conclusion that 

 formula A is more injurious to buds than formula C. While this is 

 true if the spray is applied at too late a date, it may T)e safely applied 

 at an earlier date. It should also be mentioned that the sulphur sprays 



