Recent Studies on Peach Yellows and Little Peach 33 



Suggestions for Differentiating Cases of Yellows and Little 

 Peach from Other Troubles 



It requires close study and observation to become expert in the 

 identification of yellows and little peach, especially in the early or 

 preliminary stages. Factors resulting in symptoms resembling yel- 

 lows and little peach have been mentioned and some suggestions are 

 now given to aid in tracing down and determining the cause of any 

 suspicious symptoms. 



1. The characteristic, wiry, finely branched shoots are a reliable indication 

 of yellows on budded varieties. Unbudded seedlings may produce 

 slender wiry looking shoots when healthy. 



2. If the fruit prematures much in advance of the normal season of ripening 

 and is distinctly red-spotted and blotched, it is strong evidence of yellows. 

 Prematuring of fruit as a result of yellows also is commonly associated 

 with foliage symptoms. 



3. In some seasons there is considerable red-spotting of fruits as a result 

 of weather factors or spray injuries. Study these seasonal effects thor- 

 oughly before undertaking orchard inspection for the elimination of 

 yellows. 



4. Neglect and starvation will result in weak, yellow-appearing trees, but 

 one should be able to diagnose such a condition without difficulty. 



5. If the foliage of any part of a tree is abnormally light green or yellow- 

 green in color and is curled or rolled, examine the twig or branch down 

 to the point where it joins the normal part of the tree. Look for in- 

 juries such as brown rot cankers or girdling in any form. If no such 

 injuries can be found, the tree becomes a suspicious case and may be 

 diseased with yellows or little peach. 



6. When the abnormal yellow and rolled appearance of the foliage of a 

 branch or the whole tree extends to the surface of the soil, the trouble 

 is almost certain to be located below ground unless it is a case of yellows 

 or little peach. Remove the soil from about the trunk and main roots 

 and look for girdling by borers, mice, winter injury or other factors. 

 These injuries may be located as far as 10 or 12 inches below the surface. 

 Cut into the bark upon the trunk and main roots and note whether it has 

 a healthy normal color. If it is yellow, spongy, or brown, injury is in- 

 dicated. If the injury is serious such trees are likely to show rolling and 

 yellowing of the foliage, enlarged fruits and lenticels and prematuring. 

 The fruit will seldom be red-spotted and blotched unless the tree is also 

 affected with yellows. Trees seriously girdled or weakened as a result 

 of any cause are of little value and are often best removed whether dis- 

 eased or not. A tree with yellow rolled and drooping foliage in midsea- 

 son without any root or bark injuries is a very suspicious case of an 

 early stage of yellows or little peach. In late fall when growth has 

 ceased the foliage may become somewhat rolled on healthy trees. 



7. The foliage of trees in a tilled orchard suffering from drought is always 

 wilted and flaccid and readily distinguished from the drooping but turgid 

 condition of the leaves on trees affected with yellows or little peach. 



8. Peach trees suffering as a result of poorly drained soil or certain un- 

 known, unfavorable soil factors on some well-drained soils can be dis- 

 tinguished from yellows or little peach as follows : 



The poorly drained areas in an orchard are readily traced in most 

 instances. If there is any doubt after a surface survey, an examina- 

 tion of the subsoil will usually reveal the true conditions. 



