52 N. J. Agricultural Experiment Stations Bulletin 356 



Susceptibility of Varieties 



A total of 75 varieties of peaches were grown in the experimental 

 orchards at Vineland from 1907 to 1920. Only a few trees were 

 grown of a considerable number of these varieties, so that a fair 

 comparison cannot be drawn, but where considerable numbers were 

 grown there appeared to be but little varietal difference in suscepti- 

 bility to these diseases. It may be noted that very few of the 

 Greensboro trees became diseased before 1920 and the same holds true 

 with Waddell, Mayflower and Early Wheeler. These are all white- 

 fleshed varieties of the so-called Chinese Cling group. Of Carman, 

 in orchard no. 1 there were planted 22 trees and only 9 have become 

 diseased so far, the majority of these in 1920, which is a particularly 

 good record ; but 120 trees of the same variety were planted in no. 

 3, of which 72, or 60 per cent, have succumbed. 



The writers, therefore, have been unable to observe up to the 

 present time that variety exerts any influence upon resistance to these 

 diseases. 



Replants Not More Susceptible Than Other Trees 



Complaints are sometimes made that trees set after the removal 

 of diseased trees fail to grow satisfactorily. Attention should be 

 called to the fact that all replants in orchards more than two or three 

 years of age are at a distinct disadvantage, especially where the dis- 

 tance between trees is less than 20 feet each way. Replants are often 

 set carelessly and not infrequently late in the season and receive but 

 little attention and care. They are also handicapped because they 

 are surrounded by larger trees which are able to usurp a large share 

 of the available light, moisture and plant-food. Therefore, these re- 

 plants start slowly and appear unhealthy because of unfavorable con- 

 ditions for growth. Undoubtedly many such trees have been re- 

 garded as diseased when they were healthy. 



Table 5 is compiled and arranged to show the losses due to disease 

 among the replants at Vineland in comparison with the original trees 

 set. The data are arranged so that the results may be noted at the 

 close of the years 1918, 1919 and 1920. The year 1918 gives us a 

 comparison between original trees and replants at the beginning of an 

 epidemic and in 1920 when it was at its height. 



The total average loss from disease in the original plantings in 

 1918 was 7.9 per cent, while the total average loss for all the replants 

 was 3 per cent. If the comparisons are made on the basis of 1919 



