16 BULLETIN 647, TJ. S. DEPARTMENT OF AGRICULTURE. 
on the trees it may be of great importance as a conveyor of citrus 
diseases, but the actual extent to which it increases the spread of 
diseases as yet remains to be determined. Since almost all the 
damage so far caused by the ant has been through its relations with 
the injurious citrus insects, this damage must be solely in the nature 
of an intensification of the work of these insects. Only that portion 
of such injury in excess of that normally caused by these insects can 
be due to their relations with the ants. It is, therefore, necessary to 
bear in mind that only a few of the citrus-infesting insects are of 
importance, and they cause practically all of the insect injury. The 
ant must be proved to enhance greatly the damage done by these major 
pests before a case can be made against it as a destroyer of orange 
trees. The major pests of citrus in Louisiana are four species of 
armored scale insects, the citrus white fly, and the rust mite, any one 
of which will cause more loss than all of the lesser pests, including 
the soft scales and the aphids, together. 
RELATIONS WITH THE AR ORED SCALES. 
Status of the Armored Scales of Citrus in Louisiana. 
The four important armored scale insects of citrus in Louisiana 
are, in the order of their importance, the purple scale (Lepidosaphes 
beckii Newm.), the chaff scale (Parlatoria pergandei Comst.), the 
long scale (Lepidosaphes gloverii Pack.), and the white scale (Chi- 
onaspis citri Comst.). The purple scale is the most numerous and 
destructive of the citrus scales, infesting fruit, leaves, branches, and 
trunk, and generally incrusting the branches and trunk along with 
the chaff and long scales. The chaff scale infests nearly every budded 
bearing tree in the State, incrusting especially the trunk and larger 
branches, and at times overflowing onto the fruit and leaves in con- 
siderable numbers. The long and white scales also occur on most of 
the trees, but do not become so numerous as the first two, either of 
which would outrank them both as pests. The status of these scales 
does not seem to have changed much, excepting perhaps that of the 
white and chaff scales, in the last 12 or 15 years. The purple scale, 
according to Morgan, 1 was considered one of the most dangerous 
scales in the State at that time (1893). The white scale, however, 
considered by Morgan 2 as one of the most destructive of the scales, 
causing bursting of the bark, does not now get so numerous as the 
others and causes little damage. The chaff scale, which Morgan 
states was not recognized as very destructive, 3 now must be accorded 
second place to the purple scale as a scale pest of citrus in the State. 
Dr. Howard states that the chaff scale was the preponderating scale 
of citrus at a certain plantation on Bayou Teche as early as 1880. 
* See Stubbs and Morgan, op. cit., p. 57. 2 Ibid., p. 64. 3 Ibid., p. 62. 
