264 STATE HORTICULTURAL SOCIETY. 



moisture had something to do witli the disease. Since his time many have 

 held the same view, although not much evidence appears to have been brought 

 forward to sustain it. Mr. Rutter, liowever, states that yellows was very 

 prevalent in West Chester during the rainy season of 1878. Whether the 

 formor great outbreaks in Upper Delaware, in New Jersey, Connecticut, New 

 York, Ontario, and Michigan occurred during rainy seasons is uncertain. I 

 have found no trustworthy evidence of such coincidence. On the contrary, 

 Charles W. Garfield states that yellows was much worse at Saint Joseph, 

 Mich., in two excessively dry seasons, 1871 and 1872. 



Careful rain-fall records in inches are not kept on the Chesapeake and 

 Delaware Peninsula, so far as I know; but from general entries in several 

 weather records and from newspaper paragraphs and the statements of many 

 trustworthy persons, it is beyond question that in the vicinity of Dover and 

 Still Pond, and in fact over all the upper part of the peninsula, there was 

 excessive rain-fall both in 1886 and 1887. As regards 1887, my own observa- 

 tions confirm these statements. It was very rainy — hay was a large crop ; 

 corn-fields could not be properly cultivated; wheat spoiled in the shock; 

 weeds grows amazingly; and the peach tree itself made a much larger growth 

 than in 1888. According to Dr. Henry Eidgely's daily record the exceedingly 

 rainy months of 1886 were May, June, and July; and the months in 1887 in 

 which most rain fell were April, June, July, and August. In 1887 the last one- 

 half of April, the whole of July, and the first two-thirds of August were especial- 

 ly wet, the July rainfall being enormous. In a general way the rain charts 

 of the signal service confirm these statements, and would undoubtedly be 

 shaded still more deeply in this region were they based on a larger number 

 of observations. Coincident with these two rainy seasons was a marked 

 increase of peach yellows, which seemed attributable thereto and was so attri- 

 buted, very commonly. 



One could not help noting such a striking coincidence or avoid being 

 influenced by it. Until this year, therefore, I held the view that excessive 

 rainfall, while not the cause of yellows, was a necessary factor in its rapid 

 dissemination. It seemtd wise, however, to follow the progres3 of the disease 

 another year before making very positive asser ions. It was, therefore, with 

 unusual interest that I waited the season of 188S, hoping it might be dry. 

 Fortunately, it was dry; but a careful study of the di-ease in five counties 

 showed no marked diminution in the number of newly infected trees. If 

 some orchards showed fewer new cases than in 1887, others in the vicinity 

 showed more, and still others developed the disease for the first time, often 

 in many trees (see record of examinations in numbered oruhar Is). Many 

 other orchards might be cited. I also found that all trees diseased in 1887 

 continued to be diseased in 1888, and that the disease had invaded contiguous 

 territory which was free in 1887. 



It cannot, therefore, be said that the excessive rainfall of 1886 and 1887 

 was especially favorable to the spiead of the disease, unless, as is quite likely, 

 the conditions then produced remained and continued their injurious activity 

 in the dry year of 1888. It may, however, be stated without qualification 

 that, contrary to expectation, a dry year following the two wet ones did not 

 check the spread of the disease. Kainy weather may have some influence in 

 originating a widespread epiphytotic, which is then capable of holding its 

 own (inring succeeding dry weather. On the other hand, too much influence 

 may have been ascribed tu wet seasons from the fact that diseased trees put 

 out a more abundant growth of secondary shoots in such years, and are 



