PEACH YELLOWS. 267 



deficiency of potash, such as the analyses seem to indicate, why may it not be 

 an effect of the disease rather than the cause? The amount of this substance 

 is believed to be proportionate to the vigor of growth. In weak and feeble 

 growths, such as are characteristic of the later stages of yellows, we might 

 consequently expect to find less of this element. In my judgment the 

 amount of assimilable material in the soil has little or nothing to do with 

 the deficiencies said to exist in diseased tissues. 



Again, it would seem that four analyses, however carefully made, are an 

 inauflBcient basis for so important an assumption. On this ground alone the 

 fact of any characteristic disparity of chemical composition might very prop- 

 erly be denied, or held in question, until established by many careful analyses. 

 Up to this date only a few have been made, and these are not altogether con- 

 sistent. At least half a hundred analyses ought to be made, under various 

 conditions of growth, if anything like exact information is desired. At 

 present we do not even know that trees stunted by borers, by root aphides, or by 

 starvation would not yield chemical results identical with those given by 

 trees suffering from yellows. The probabilities are that they would. 



Moreover, knowing from personal experience how easy it is to make mistakes, 

 I am inclined, with all due respect to those who advocate this theory, to think 

 there may also be a possible error of fact as to the alleged cures. 



The Amherst trees were set, in 1870, only 12 feet apart ; were neglected 

 for five years, and did not receive treatment for yellows until 1878. Only the 

 trees least affected were treated. These became green, bore fruit, and were 

 pronounced cured at the end of three years. We are not told who identified 

 the disease, or whether the trees in question (the identical ones treated) bore 

 the premature red-spotted peaches and the characteristic shoots. Is it not 

 possible that these trees may not have had genuine peach yellows, such as has 

 destroyed the orchards in Michigan and Delaware? I have frequently seen 

 yellow, starved looking trees which were not suffering from yellows, and 

 these, too, in orchards where the real disease was j)resent. It is easy to mis- 

 take something else for yellows if one has had but little experience with the 

 disease. The statements that these trees were on an impoverished hill ; that 

 they were set only 12 feet apart; that they were eight years old when the 

 disease was discovered, and that the trees in the richer bottom remained 

 healthy, all lead me to think that some or all of them may have been simply 

 starved trees, in which case they would naturally respond quickly to suitable 

 food. On any other assumption I am at a loss to harmonize my own observa- 

 tions with the statements of Dr. Goessman and Professor Penhallow, unless, 

 indeed, there should exist a difference in judgment as to what constitutes a 

 cure. My own criterion is that the restored tree must again bear healthy 

 fruit, ripening at the normal time. Any substance which accomplishes less 

 than this is not a remedy, but at best only a palliative. 



Professor Penhallow' s field work at Houghton farm in 1883 would also 

 appear to offer insufficient data for judgment as to the real merits of the 

 muriate of potash. One tree only was cured of yellows. This had never 

 borne fruit, but was one of a few young trees procured that year from 

 Eochester, N. Y. Is there not a possibility that this tree was suffering from 

 a cause or causes other than that which produces yellows, although manifest- 

 ing symptoms somewhat resembling it? This cure was effected in 1883. I 

 am unable to say what has been the subsequent history of this tree. It would 

 be interesting to know if it continues healthy and is productive. 

 ^Has this remedy given any more definite and satisfactory results in the 



