20 BULLETIN 647, U. S. DEPARTMENT OF AGRICULTURE. 
cultivation and pruning received by the trees. There was no ap- 
parent difference between the two sets of trees as to abundance of 
armored scales. 
RELATIONS WITH THE SOFT SCALES. 
Status of the Soft Scales of Citbus in Louisiana. 
Only four of the six principal citrus-infesting species of soft scales 
occurring in Louisiana have been discovered in the orange section 
of Plaquemines Parish. These are the soft brown scale {Coccus 
hesperidum L.), the citrus mealybug (Pseudococcus citri Risso), the 
Florida wax scale (Ceroplastes foridensis Comst.), and the barnacle 
scale (O. cirrlpediformis Comst.). No injury to citrus, serious or 
slight, ever has been attributed to the last two scales in the history of 
the orange industry in the United States, nor do they now cause 
noticeable injury to citrus in Louisiana. The first two are the only 
citrus soft scales occurring in sufficient numbers in the orange groves 
to attract attention. 
Morgan 1 states that the citrus mealybug was very abundant in 
some of the orchards of Louisiana in 1893, especially in those well 
protected from winds and in thick-growing trees such as the man- 
darin, but was not a particularly serious pest at that time. These 
statements apply equally well for all practical purposes at present. 
The mealybugs occur scatteringly throughout the groves of Plaque- 
mines, St. Bernard, and Orleans Parishes. They usually make a 
strong start in the spring and early summer and threaten seriously 
to infest certain orchards, but between the middle of June and the 
first of August they are brought under control by their natural ene- 
mies. Infestation goes the same course on fig trees in yards in New 
Orleans, except that the mealybugs are at times somewhat slower in 
being subdued there than in the orange groves. 
Regarding the soft brown scale, Morgan's statement that "it ap- 
pears and disappears, being kept in check by parasites, and for this 
reason has not attracted the attention of the orange growers " 2 also 
applies to-day. Its status is still essentially the same, though it is 
undoubtedly true that this scale will now be found in larger groups, 
in places, because of abundant attendance by the Argentine ant. It 
occurs upon nearly every budded orange tree over 3 years of age in 
the State, and also on banana, rose, and loquat in the orange groves. 
The important thing is, however, that it does not cause death or seri- 
ous injury even to the twigs which it inhabits, does not blemish the^ 
fruit, and is not of noteworthy economic importance even in orchards 
overrun by ants. 
1 Op. cit., p. 69. * Ibid., p. 68. 
