24 N. J. Agricultural Experiment Stations Bulletin 356 



of or curing yellows. The question, however, is brought forward 

 frequently, and further evidence is furnished by the Vineland or- 

 chards on both yellows and little peach. 



The fertilizer treatments varied from the check, or no-fertilizer 

 treatments, to an annual application per acre of 10 tons of stable 

 manure plus 100 pounds of ground bone, 200 pounds of acid phos- 

 phate and 150 pounds of high-grade sulfate or muriate of potash. 

 One plot received nitrate of soda at the rate of 250 pounds per acre 

 in addition to phosphoric acid and potash in amounts equal to those 

 mentioned above. At times, non-fertilized or lightly fertilized trees 

 would appear more susceptible to yellows and little peach than trees 

 receiving liberal amounts of plant-food. In other cases the reverse 

 would appear to be true. These observations over a period of 14 

 seasons agree with those of Smith. It should be noted, however, 

 that good culture and liberal applications of plant-food may keep 

 diseased trees more vigorous and delay general breakdown and death. 



Factors Which Determine Size and Time of Maturity of the 

 Fruit on Normal Trees 



The symptoms of yellows and little peach are so similar to those 

 produced by other factors interfering with the growth of the peach 

 tree that an understanding of the normal plant-food metabolism in the 

 tree and the influence of the common factors of its environment are 

 necessary before one can clearly understand an extended discussion 

 of yellows and little peach. 



In order to produce desirable fruit, a tree must be able to main- 

 tain a certain amount of growth and vigor. To this end, both plant- 

 food and moisture are essential. Given favorable conditions for 

 growth, the development of the tree depends upon the taking up of 

 crude plant-food by the roots, photosynthesis in the leaves, and trans- 

 location of the elaborated foods. In a normal tree, the elaborated 

 plant-food to a large degree is stored up as starch in the leaves and 

 young stems during the day ; is converted into sugar at night, and is 

 then available for the support of growth and development in various 

 parts of the tree or for storage for future use. When the tree is 

 young this food is used for growth but when the tree reaches the 

 bearing stage, it is used for both growth and fruit production. 



It has been observed that rapidly growing peach trees may 

 set a few fruits as early as the beginning of the second sea- 



