50 N. J. Agricultural Experiment Stations Bulletin 356 



sponding age year. There was a large increase in 1917, another in 

 1918, then a slight decrease in 1919. The increase in 1920 was large, 

 but the percentage loss was smaller than in orchard No. 1. The 

 total loss, however, was 60.18 per cent of the original planting. 



Orchard no. 3 was planted in 1912, and consists of 496 trees, ar- 

 ranged in 31 rows of 16 trees each. This orchard lies south of 

 orchards no. 1 and 2. The losses from this orchard appear in 

 table 4. 



As in the other case, the first diseased tree was observed in the 

 third year of the life of the orchard. From then on, however, the 

 number of trees infected increased gradually until 1916, with a large 

 increase in 1917 (the sixth year of the life of the orchard), only a 

 slight increase in 1918, but in the following years very large in- 

 creases, 25 per cent of the original planting of trees being removed 

 in 1920. In this orchard there were two trees (one in 1917 and one 

 in 1919) that showed evidence of little peach on one side and yel- 

 lows on the other side of the tree. 



Data from Vineland Orchards Show Losses from Quiet Period to 



Epidemic 



Peach yellows epidemics have occurred periodically in the vicinity 

 of Vineland about once every ten or fifteen years. When the de- 

 partment of horticulture began experimental work at Vineland in 

 1907 the district had just passed through one of these epidemics, 

 and located near the site of the experimental orchards was a small 

 orchard about 6 years of age in which every tree was infected with 

 yellows. 



The results in tables 2, 3 and 4 show that another epidemic was 

 under full headway in 1920. One interesting difference between the 

 two epidemics is that the one about 1905-1907 was confined mainly 

 to yellows, since there were only two trees affected with little peach in 

 the locality, while in 1920 the losses were largely due to little peach. 

 A close study of the history and behavior of these two diseases and 

 the rosette leads us to suspect that they may be different forms of 

 the same trouble and that climate is an important factor in causing 

 the variations. 



Figure 25 clearly shows the losses in the Vineland experimental 

 orchards from the quiet period following the epidemic of about 1905- 

 1907 to that of 1920. It is believed that this depicts correctly what 

 occurs in districts where periodical epidemics of yellows occur. The 



