CITRUS MEIANOSE AND ITS CONTROL. 57 
Bordeaux-oil emulsion applied during the spring months has a very 
marked beneficial effect upon chronic cases of die-back, the principal 
symptoms of which are " ammoniated " fruit, multiple buds, gum 
pockets, bark excrescences, and stained terminals. 
In groves that annually produced crops of poor quality, due to 
" ammoniation," prompt and almost complete relief to the current 
crop has been observed repeatedly when Bordeaux-oil emulsion was 
applied during the spring months. This is particularly true of old 
seedling orange groves in flatwoods soils and where foot rot is accom- 
panied by " ammoniation." 
Frequently orange and grapefruit trees that are in a run-down 
condition with symptoms of wither tip due to obscure causes resume 
normal growth following an application or two of Bordeaux-oil 
emulsion made during the melanose spraying season. 
COST OF SPRAYING 
The cost of spraying is difficult to arrive at, but on the average 
a power outfit with a team and three men seldom applies more than 
1,600 gallons a day, frequently 1,200 gallons or less. Spray ma- 
terials should not cost more than 1% cents a gallon for Bordeaux- 
oil emulsion. An average-sized mature orange or grapefruit tree 
that produces from 3 to 4 boxes of fruit annually requires from 8 to 
10 gallons of spray to wet all parts thoroughly. 
Since the cost of spray materials in Bordeaux-oil emulsion rep- 
resents about 50 to 60 per cent of the entire cost of spraying, the gross 
cost of spraying should not be more than 30 cents a tree or more 
than 10 cents a box, and frequently it is less than 8 cents a box when 
all costs are considered. The total annual cost of all necessary 
fungicidal and insecticidal applications for the average citrus grove 
in Florida oftentimes does not amount to more than 15 cents a box of 
fruit. Although spraying is a slower operation than dusting, it is 
not likely to be more expensive. 
VALUE OF SPRAYING 
To sum up, in the light of present knowledge, spraying is the only 
means of controlling melanose that is economical and effective for 
use in normal mature groves. Sulphur sprays have little effect upon 
the disease, the weaker copper sprays are only partially effective, but 
standard 3-3-50 Bordeaux plus 1 per cent oil as emulsion applied 
before much infection takes place gives an excellent control of the 
disease. 
SPRAY INJURY 
Generally speaking, citrus fruits are much more resistant to spray 
injury than are peaches or apples. Nevertheless, all of the principal 
types of sprays used in citrus groves are capable of producing distinc- 
tive forms of injury. 
Copper-spray injury. — The orange fruit or foliage is seldom in- 
jured by a reasonable number of properly made applications of 
Bordeaux mixture or Bordeaux-oil emulsion. When injury does oc- 
cur on the orange the trouble is likely to be due to the water used in 
spraying, or to poor spreading of the spray, or in rare instances to 
