36 N. J. Agricultural Experiment Stations Bulletin 356 



buds from trees in various stages of the disease were used in propa- 

 gation work. The appearance of diseased trees in the Experiment 

 Station orchards which had been under close observation from the 

 the time of planting furnished sources for buds. The results of this 

 propagation work have very clearly established the fact that the 

 time of appearance of prominent symptoms of disease in the budded 

 stock varies greatly according to the tree from which the buds were 

 cut, and also according to the portion of the tree from which the 

 buds were taken. 



Early in July, 1912, a Fitzgerald tree in orchard no. 2 at Vine- 

 land (fig. 22) suddenly developed a large number of characteristic 

 yellow shoots. Previous to this time, the tree had not even dis- 

 played the common early symptoms of the disease, even as late as 

 June of the same year. Buds from this tree taken for propagation 

 in August gave very striking results the following spring. Nursery 

 stock budded with material from this tree in August began to develop 

 characteristic yellows shoots immediately the following spring, as 

 illustrated in figure 23. In one instance the bark about an inserted 

 bud became attached to the stock but the bud itself died, yet the stock 

 began to develop characteristic yellows growths in early spring, 

 which rapidly became more prominent as the summer advanced. 

 Figure 24 shows the appearance of this seedling in the summer fol- 

 lowing the budding. The main crotch of the seedling was 13 inches 

 above the point where the inserted bark was attached and one of the 

 yellows shoots had developed at a point d> l /> inches above the crotch 

 by July 7, 1913, or less than a year following the inoculation. Some 

 of the trees propagated with these diseased Fitzgerald buds did not 

 show prominent symptoms of the disease until the latter part of the 

 summer following budding. A few of the trees stopped growth in 

 the late summer during a dry period and when they resumed growth 

 after a rain the characteristic shoots appeared. This entire lot of 

 stock was carried over until the spring of 1914, but a large percent- 

 age of the plants died. Two, however, remained alive during 1914, 

 but made scarcely any growth. 



This original Fitzgerald tree appeared to have a most virulent form 

 of yellows and in an exceptionally short time trees budded from it 

 developed very pronounced symptoms of yellows. Late in the same 

 summer, August, 1913, buds were selected also from branches of an 

 Elberta tree which developed premature fruit for the first time in 



