1 i 2 GARDENING FOR THE SOUTH. 



Die Back (Exanthema)* This disease is also known 

 only in Florida, and is widely distributed over the State. 

 As the name implies, the disease causes the vigorous 

 new growth to die back in early spring, and the yield of 

 fruit is consequently reduced. 



" The order in which the symptoms appear and their 

 severity vary greatly, but are generally as follows: The 

 first sign of the disease is the unusually dark-green color 

 of the foliage, rank growth and large, thick-skinned fruit. 

 These symptoms are soon followed by the staining and 

 dying back of a few twigs, and by brown stains formed on 

 some of the fruits. The fruits developed are prone to 

 split and drop prematurely. In the first stage of the 

 disease either the stained fruit, or the stained, dying twigs 

 must be present to determine with certainty the presence 

 of the malady. Trees affected with the disease may grow 

 for years and show only one of these character symptoms; 

 in other cases all symptoms may be present, but to a very 

 slight extent, so that careful search must be made to find 

 them. As the disease progresses the brown staining of the 

 fruit and twigs become very abundant, and the dying back 

 of the twigs occur all over the tree; eruptions form on the 

 young and old twigs; nodal swellings, due to the gum 

 pockets, become very abundant, and the tree assumes 

 the dense foliage and regular outline described above. 

 In this stage of the disease many fruits set, but they 

 usually turn yellow, become stained, split and fall before 

 maturity, only a few, if an}^ reaching full size. Soon 

 the gum eruptions extend to the old limbs and these die 

 back. The rank growth becomes limited to the center 

 of the tree; here branches grow luxuriantly for a time, 

 only to become stained and die back later.'' 



Treatment. — Reducing the amount of highly nitro- 



: Bulletin 8. Vegetable Physiology and Pathology, U. S. Dept. Agri. 



