16 PEACH YELLOWS. 



II. INOCULATIONS. 



Experiment 1. The trees selected for tins series of inoculations were 

 grown from Smock seed, procured in Kent County, Maryland. They 

 formed part of a large nursery owned by Norris Barnard, Still Pond, 

 Maryland. When first seen the seedlings were about 5 mouths old, and 

 were being worked for commercial purposes. They numbered more 

 than 100,000, and all presented a very healthy, thrifty appearance. 

 The trees devoted to the experiment were in one corner, and not dif- 

 ferent in appearance from the rest. 



The buds for inoculation were cut in an orchard on the Bay farm of 

 James S. Harris, Still Pond, Maryland. They came from diseased shoots 

 on 15 or 20 vigorous, 4-year old trees. These trees had shown no symp- 

 toms of disease until that summer, when they bore the red-spotted, pre- 

 maturely ripened fruit as well as the characteristic shoots. 



The buds were cut August 12, 1887, and inserted the same day. The 

 manner of insertion was like that ordinarily practiced in reproduction 

 by budding, i. e., the bud, with a portion of the surrounding bark and 

 often some of the underlying wood, was inserted under the bark of the 

 seedling about 6 inches from the ground, by means of a T-shaped slit. 

 The insert was then bound into place securely by strings, which were 

 cut or loosened at the expiration of ten days. According to their size 

 the trees received one or two buds, none more than two. 



In most instances the wood and bark which were inserted healed on 

 quickly and retained their vitality over winter, but there was no growth 

 from the buds that autumn, nor any symptoms of disease in the stocks. 

 The seedling tops were removed in the spring. 



One year from budding these trees were reexamined. Three-quarters 

 of the inserted buds had failed to push. Of the rest some had grown 

 into diseased shoots; others (a few) had grown into shoots which did 

 not yet show the characteristic symptoms of yellows. The effect on the 

 stocks was marked. About 34 per cent of the whole number (202) had 

 become diseased beyond question, while only 23 per cent were entirely 

 healthy. Some of the trees had died during the summer, evidently 

 from the effects of the disease. A few yet living were badly affected, 

 but most of them showed only slight symptoms. Nevertheless, here 

 were the feeble shoots and the winter buds germinating 6 mouths in 

 advance of the proper time. 



The evidence seemed to be overwhelming and complete, for while 

 the experiment was performed in a region were the disease occurs it 

 was on a large scale, and moreover the remainder of this nursery and 

 other nurseries in the same region, subject so far as known to the same 

 influences, were examined in vain for anything which would correspond. 

 The 542 trees in adjoining rows, which were examined critically for 

 comparison, showed no traces of the disease, although all other condi- 

 tions appeared to be identical. The fact that peach yellows in that 



