32 
from the trunk of tbe tree. In addition a study should be made of the 
relative adaptability of the various fertilizers to the particular soil. 
This is properly the function of public experimenters, but much can be 
accomplished by individuals if sufficient care is exercised. In one of 
the finest groves visited the principal fertilizer used consisted of decay¬ 
ing vegetable rubbish piled between the rows of trees. Weeds were 
allowed to grow in the intervening spaces thus covering the light- 
colored soil, and preventing much of the undue reflection of light and 
heat that is so common where clean culture is practiced. 
III.—BLIGHT. 
(Leaf curl. Wilt, Go-back.) 
(1) Nature of the disease .—The leaf blight, leaf curl or leaf wilt, as it 
is variously called, first makes its appearance on certain branches, and 
may be recognized by the curled or wilted appearance of the leaves, 
which also turn a sickly yellowish color and after a short time drop 
from the tree. The twigs at the ends of the branches also die, and if 
new ones appear they soon present the same sickly hue; the bark, espe¬ 
cially on the upper side of the branches, becomes u hide-bound, 77 and 
later splits open on either side, leaving a dead space between the rup¬ 
tures. The fruit grows smaller, but is otherwise not affected. Grad¬ 
ually other branches become infected, and if the tree is left to itself it 
finally dies down to the root. As the disease progresses new shoots 
constantly make their appearance below the infection, appearing robust 
at first, but as the infection descends they too become wilted, and finally 
those only appear healthy that spring from the root. If the tree is vig¬ 
orously pruned at the first appearance of the disease and well fertilized, 
it will apparently recover, but after a little will relapse or go back to 
its former condition. This peculiarity of the disease has given rise to 
to a popular name which it does not seem desirable to perpetuate. 
The disease does not seem to attack trees before they reach maturity, or 
before they are 10 or 12 years old. When one tree becomes attacked, 
adjoining trees, either during the same season or more likely during 
the following season, will be affected, so that the diseased trees appear 
in groups. Sporadic cases occasionally occur, but the above condition 
is so nearly universal as to make it extremely probable that the disease 
is contagious. 
(2) Distribution .—Bad cases of this disease are found as yet in only 
a few localities where the orange groves have long been established. 
While it is evidently not a new disease its ravages have only recently 
extended sufficiently to give alarm to cultivators All things consid¬ 
ered, this disease is the most dangerous that has yet appeared among 
the orange groves, and a study of its causes and cure demands immedi¬ 
ate attention. 
(3) Causes .—Nearly as many causes are assigned for the disease as 
there are cultivators whose groves are affected by it. Some assign it 
