FLORIDA STATE HORTICULTURAL SOCIETY 
111 
food as grapefruit and tangerine trees of 
the same age and size. Then some varie¬ 
ties of oranges may require different 
methods of feeding. 
It may be interesting to mention most 
of the symptoms and indications of die- 
back—bark excrescence; gum pockets; 
stained terminal branches and twigs; 
staining of the leaf, petiole and midrib; 
“S”-shaped and droopy terminal growth; 
deep green color and large coarse leaves; 
frenched, pointed leaves—these are often 
fleshy and brittle; bunchy growth—a ten¬ 
dency toward multiple buds; wood flexi¬ 
ble—too easily bent or twisted; fruit 
coarse; fruit scarred with ammoniation 
markings; fruit too hard and too firm— 
lacking in resiliency; wood too angular 
and not well filled out; stubby growth— 
especially if bunchy and possibly 
frenched; malformed, crinkled leaves— 
not caused by wind or mechanical injury; 
the wood may be dark and hardened. 
There are several other conditions that 
will induce many of the above symptoms 
of dieback. Poor drainage will bring on 
a dieback condition. In this connection 
it might be well to mention the effect of 
clay or some other impervious layer being 
close to the surface even though the soil 
seems to be perfectly drained because it is 
on high land and often well above the 
lakes that may be near. The result of this 
layer being close to the surface is that the 
trees get all the food that is put on the 
ground as the only leaching that can take 
place is laterally and often this is not very 
rapid. This, when not taken into consid¬ 
eration, will bring about a condition of 
overfeeding. 
Another condition that often exists in 
old seedling groves and in some of the old¬ 
er budded groves is that the trees are set 
very close together. When this is the case 
the trees are so crowded that by the time 
they are mature the actual leaf surface or 
top of the tree is much smaller than a tree 
of the same age having room enough to 
expand and make a growth on the sides of 
the tree. When this is not taken into ac¬ 
count the close set trees are often given the 
same amount of fertilizer a normal shaped 
tree would get. The result is that the close 
set trees are often over-fed and the fruit 
coarse and ammoniated. 
Deep plowing and excessive and deep 
cultivation will tend to cause dieback and 
especially a frenched condition as will be 
mentioned later. 
Having trees set too deep will cause 
trouble. The crown roots should be at 
ground surface as is brought out in anoth¬ 
er paper on the program. 
Ammoniation is the effect of the die¬ 
back condition of the tree as shown by the 
fruit. The markings are very character¬ 
istic yet when not very severe some have 
trouble distinguishing it from Melanose. 
A simple comparison of the two may be 
helpful. The Melanose markings affect 
the surface and the dark scab-like spots 
may be lifted up disclosing tissue of fairly 
normal color underneath. The ammonia¬ 
tion markings cannot be so easily lifted 
off and the tissue underneath has a stained 
and often brownish appearance. Another 
method of distinguishing them is to cut a 
small wedge-shaped piece out of the rind 
through the spots in question and note the 
color of the underlying tissues. Badly 
