131 



The practice here recommended of extirpating all cases as they 

 appear is now largely followed by those who have had the most experi- 

 ence with blight and who know the uselessness of supposed remedial 

 treatments. In all badly infected regions concerted action is highly 

 desirable, but even if this cannot be secured the grower should not be 

 deterred from eradicating the diseased trees from his own grove. 

 Aside from the fact that such a course probably lessens the spread of 

 the malady, it is the cheapest and best policy. 



DIE-BACK OR EXANTHEMA. ( ^ ) 



The disease of the orange and other citrus fruits, commonly known 

 as die-back, is widely distributed throughout the orange region of 

 Florida but is not known to occur in any other part of the world. The 

 name "^die-back" originated from the behaviour of trees affected, a few 

 inches of the vigorous new growth die back in early spring. The 

 disease is not much feared by growers, because it is apparently not 

 contagious ; but while the damage it causes in a single grove may be 

 slight, the total loss, on account of its very widespread occurrence, is 

 nearly as great as that resulting from any other disease affecting the 

 orange. The malady is well known to most orange growers, but is 

 generally poorly understood. Tt was first accurately described by J. 

 H. Fowler (^) in 1875. When and where it first appeared has not yet 

 been determined Growers have kiiown of its occurrence for years, 

 presumably ever since orange culture became common in the State. 



The damage caused by die-back is much greater than is usually es- 

 timated. Many groves have suffered i >y years from slight attacks of 

 the disease, the damage being caused mainly by the excessive drop- 

 ping of the fruit and by the coarseness and staining of that which 

 remains on the trees. In some severe cases due to improper fertilisa- 

 tion and cultivation, groves have been badly injured and almost the 

 entire crop of fruit lost. Frequently much loss is incurred by plant- 

 ing trees on improper soils and continuing to cultivate and fertilise them 

 for years after they contract the disease. Almost every grove in the 

 State has a few cases of this disease. Trees growing in the vicinity of 

 stubles, chicken houses, privies, e'c. are the ones generally affected, 

 and also those growing on the margins of lakes, or on low, wet, poorly 

 drained soils. 



The diminished productiveness of trees badly affected with die- 

 back, together with the splitting and falling of much of the fruit and 

 the disfigurement and coarseness of that which does develop, makes 

 such trees almost wort n less. The malady causes great loss of fruit, 

 renders moreof poor quality, frequently pe manently stunts the tree and 

 eventually kills it. The annual loss resulting from die-back in Florida 

 may be conservatively estimated at about ^100,000. 



(1) From the Greek, meaning an eruption or pustule. 



(2) Fowler J. H., On the Die-back in Orange Trees (Proceedings of the Florida 

 Fruit Growers' Association, annual meeting January, 1875; reprinted : Florida, 

 its Scenery, Climate, and History, Sydney Lanier, 1876, J. B. Lippincott & Co., 

 Philadelphia, Appendix, pp. 281-290). 



