ORANGE DISEASES. The orange, in com mon with many of the other citrus fruits, is sub ject to a number of injurious diseases by which the trees are destroyed or stunted in their growth and the fruit injured or rendered un sightly. One of the widest spread diseases, espe cially destructive of and sweet oranges, is the 'foot-rot,' which is of unknown origin. but occurs in Florida, California, Europe. and Aus tralia, and, according to estimates, has ea used annual losses of more than $100,000 in Florida alone. It may be recognized by copious exuda tion of gum near the base of the tree. sparse, small yellow leaves, and dead small hranehes, and patches of dry bark which fall off. Other centres appear and the disease spreads until the whole tree is girdled. Removing the soil from around the crown of the tree seems to be the most effective treatment. Over cultivation is to be avoided and good drainage secured. 'Die-haek,' so named from the dying of the young twigs for several inches from their tips, is a serious trouble in Florida. No variety or age of tree appears exempt from this disease, which seems to be due to malnutrition, resulting in part at least from improper cultivation and improper drainage. The fruit on trees is not abundant, ripens prematurely, and frequently splits, drop ping from the tree before ripening. Withholding nitrogenous fertilizers, stopping cultivation, mulching about trees and thorough drainage have given good results in overcoming this disease. The sooty mold (JIclioht camellia') is a fungus that follows scale and other insects which exude honeydew upon the trees. It covers the leaves and stems, interfering with their functions, and renders the fruit imso table by the covering of black, almost felt-like mycelium. By destroying
the insects with resin washes or by fumigation, the excretion of honeydew (q.v.) is stopped and the sooty mold disappears. Not only citrus trees. but many others are subject to this pest. 'Blight.' a destructive and apparently contagious disease of unknown cause, for which no cure is as yet known, seems to attack bearing trees only. The leaves suddenly wilt, even in rainy weather; numerous sprouts appear upon the trunk, and die after a season or two. The trees blossom pro fusely the season following the wilting, lint are usually leafless, and set few fruits and ripen fewer. A single branch, or the whole tree, may he affected. but in any ease the tree is finally destroyed. The scab is due to a species of Cladosporium winch causes warts or scabs on the leaves and fruits, especially of lemons. Thor ough spraying with ammoniacal copper carbon ate will prevent this disease. At least five ap plications should be given. See Colored Plate of CITRUS FRUITS.
Consult: Bonavia, Cultivated Oranges and Lemons of India (London, 1S90); Risso and Porteau. Histoire naturclle des o•auiqers (Paris, 1822) ; ruitutJe of the Citrus, in California State Board of Horticulture Report (Sacramento. 19021: Stills, Citrus Fruit Culture, California Agricultural Experiment Station. Bulletin 138; 11;u-court. Florida Fruits (Louisville, Ky., 1886) ; Wiekson, raliforn io Fruits( San Francisco, 15911 B. Alifio. El naranjo (Valencia. 1900) : Treatise and Handbook of Orange Culture in Florida, Louisiana, and California (4th ed., New York and Jacksonville. 1892).