12 
BULLETIN 134, TJ. S. DEPARTMENT OF AGRICULTURE. 
THE BLACK SCALE. 
Saissetia oleae Bern. 
DISTRIBUTION AND INJURY. 
The black scale is generally distributed throughout the Mediter- 
ranean citrus sections. (Fig. 2.) It varies in numbers from an occa- 
sional scale to numerous specimens forming a complete incrustation on 
the twigs and branches, and in injury from an insect of no commer- 
cial importance to one doing much damage through the quantity of 
sooty-mold fungus found on the trees and fruit. 
In the most important orange section of the Mediterranean 
countries, that of Valencia, Spain, the black scale is, according to our 
standards of judging, entitled to rank first among the citrus fruit pests. 
This statement is at least true for the years 1912 and 1913. In all of 
the scores of packing houses visited during the month of March, 1913, 
Tr/po// 
Sa/da 
Legend- 
x /?epresenfs ft?e more important 
c/trc/s sect/ons of tne Afetf /terra nean /?eg/or?. 
Fig. 2.— Distribution of insect enemies of citrus fruits in Mediterranean countries. (Original.) 
from a half dozen to 15 or 20 women were seen washing fruit to remove 
the sooty-mold fungus occurring as a result of black-scale infestation. 
In some cases the sooty mold was due to the mealy bug (Pseudococcus 
citri), but infection from this source would amount to only a small 
percentage of the total. During July, 1913, when the section was 
again visited, numerous young were seen on the leaves, which, barring 
a heavy mortality later, would furnish the same conditions for the 
season following. In numerous groves around Burriana, Spain, the 
sooty-mold fungus was seen to form a complete coating over all the 
upper surface of the leaves, branches, and fruit, and such a severe 
incrustation of scales occurred as actually to kill many of the smaller 
twigs, and in some cases even the larger branches. 
The greatest injury from the black scale was seen in the "Plana," 
or level district opening to the sea north of Valencia, and centering 
around Burriana. The conditions here are much the same as in the 
Spanish, Escania negia; Italian, Cocciniglia delV olivo. 
