Recent Studies on Peach Yellows and Little Peach 39 



gan to develop a few wiry shoots in June. Others hegan to show 

 symptoms of yellows in the leaves, while some still appeared normal. 

 The trees gradually became less vigorous and more sickly during the 

 next two years and were finally removed to make room for improve- 

 ments. 



Young trees suspected of being in the early stages of yellows and 

 little peach have been closely watched at the New Jersey stations at 

 different times and have almost invariably developed the advanced 

 symptoms after three or four years. These and other observations 

 indicate that it requires several months at the earliest for yellows to 

 develop in a tree sufficiently for true symptoms to occur, and further, 

 that yellows may be present in a tree for from one to four seasons 

 before even suspicious symptoms appear. In other words, trees may 

 appear perfectly healthy and normal for one or more years, even 

 when actually infected with the disease. 



When buds are cut from trees showing very slight symptoms of 

 the disease, it is quite likely that nursery trees may be produced from 

 them which will not show advanced stages of yellows for three or 

 four seasons after planting. The writers have occasionally observed 

 trees developing yellows very suddenly the fourth summer after plant- 

 ing. It seems probable that some of these trees were diseased before 

 they left the nursery. 



Still further propagation work was conducted in the fall of 1913 

 from several trees in the experiment station orchards. A Moore's 

 Favorite tree developed the yellows on a very small branch in June, 

 1913. The remainder of the tree appeared perfectly normal, ripen- 

 ing its fruit in a normal manner and at the usual time. Buds were 

 cut from the diseased portion of the tree and inserted in nursery 

 trees and the resulting trees developed characteristic yellows shoots 

 on the stock during the summer of 1914. Trees produced from buds 

 from the apparently healthy branches remained normal during 1914, 

 but gradually developed yellows until all were affected by 1918. 



Inoculation with Juices 



In 1916 several attempts were made to inoculate healthy trees with 

 juice from the leaves and fruits of diseased trees. Leaves and 

 twigs from the diseased Fitzgerald nursery trees were crushed and 

 some Triumph buds soaked in this solution for 24 hours and then 

 budded into healthy trees. For some reason the buds failed to grow 

 and the trees remained healthy. In another instance solutions were 



