54 N. J. Agricultural Experiment Stations Bulletin 356 



still healthy in the eleventh season. All the evidence at Vineland 

 indicates that trees replanted in the place of diseased trees are no 

 more likely to contract the disease than any others in the orchard. 



Trees of All Ages Become Affected During an Epidemic 



During periods between so-called epidemics of yellows and little 

 peach very few trees become affected with these diseases until they 

 are at least in their fourth or fifth season's growth, unless they were 

 diseased when planted. In orchard no. 1 the loss was less than 1 

 per cent until the sixth year ; in no. 2, until the fourth year, and in 

 no. 3, until the fifth year. Table 5, however, clearly shows what 

 happens at the height of an epidemic. The losses in the replants in 

 1920 range from 3.7 per cent among 2-year-old trees to 33.3 per cent 

 among 7-year trees and older. The older trees suffer the most, but 

 toll is taken from trees of all ages. 



'■>% 



Fig. 26- 



-Replanted Tree in Northwest Corner of Orchard No. 2 

 That Made a Good Growth 



Course of Spread of Yellows and Little Peach a Puzzle 



All manner of theories are advanced from time to time as to fac- 

 tors affecting the spread of these diseases. This is not to be won- 

 dered at, since the diseases are so inconsistent and variable in be- 

 havior. Evidence is discovered which appears to establish some fact 

 or principle, but later equally strong evidence is found which tends 

 to prove the opposite. 



