PEACH YELLOWS AND PEACH ROSETTE. 189 



places made vacant by the removal of diseased trees. This orchard also 

 appeared to be a good place to try the resisting power of healthy trees. 

 Yellows first developed in 1886 and is still present, the cases having 

 amounted to over twenty-five per cent, of all the trees. The disease is also 

 very prevalent in other orchards in the vicinity, including a younger one 

 on the same farm. 



Mr. Harper received 125 trees — fifty Mountain Rose and seventy-five 

 Crawford's Late. All were healthy, of medium size, and in good condition 

 for planting. Part of them were set in November and the remainder in 

 early spring. In some cases the diseased trees were removed just previous 

 to this planting; in others, they had been out for a year or two. The 

 peach upon plum were not set in a body, but were scattered among the 

 large trees. 



I saw them the last of May, 1890, at which date they looked more 

 promising than either of the other plantations. They were reexamined 

 October 11, 1890, but many were choked and overgrown by weeds so as 

 to be scarcely visible. Part of them had also been injuriously shaded by 

 the older trees. Some were dead and very few had made a satisfactory 

 growth, but none were suffering from yellows. Their bad appearance was 

 attributable in part to neglect. Young trees set into older orchards 

 require special care. 



(c) The remainder of the trees — seventy-five Mountain Rose, one hundred 

 Crawford's Late, and one hundred and seven Crawford's Early — were set 

 on Dr. W. S. Maxwell's farm, at the mouth of Sassafras river, Kent county, 

 Maryland. The two acres selected for this orchard are on a level hilltop, 

 overlooking orchards No. 1 and No. 18 of my first report. This field seemed 

 very well adapted to the experiment, having been already once in orchard 

 and being in the center of a region of diseased orchards. The remnants of 

 the first orchards, about seventy-five trees in all stages of yellows, were 

 removed in the spring of 1890. They were then 9 years old, i. e., set nine 

 years, and were the last to become affected. The rest of the trees had 

 succumbed earlier and were dug out at various times, most of them in 1888. 

 The trees had grown vigorously and were large. 



The peaches on plum roots were received November 7, and were set the 

 same day, midway between the places occupied by the old trees. Three 

 fourths of these trees were very fine; the rest were small. They were set 

 shallow with a view to lessening the attacks of borers. 



About one pound of unleached, hardwood ashes was distributed around 

 each tree at planting, and tomatoes with phosphate were grown in the 

 field in the summer of 1890. 



The black peach aphis appeared upon the tops of these trees in early 

 spring and destroyed many of them. The remainder were seen as late as 

 the last of May and then promised well. 



These trees were reexamined October 8, 1890. At that time eighty-eight 

 were dead, mostly from the attacks of the black aphis. Of the remainder, 

 forty-two were stunted and yellowish like similar trees in Mr. Greene's 

 orchard, while one hundred and fifty-two were very thrifty and still bore 

 dark-green foliage, In the former, in every case, the peach top had over- 

 grown the plum stock, producing a distinct bulge. In the latter the stocks 

 had kept even pace with the growth of the tops, and the abundant foliage 

 was still vigorous. In fact, I have seldom seen finer yearling trees. None 

 of these trees showed any signs of yellows. 



The five trees which furnished the buds were reexamined very carefully 



