THE CITRUS WHITE FLY: FOOD PLANTS. 39 
On March 27, 1907, near the laboratory, then located in the grove 
of Mr. J. M. Cheney, a striking example of the attractiveness of the 
umbrella tree was observed. The tree referred to was about 25 feet 
high and the leaves which were on the average only about half 
developed were estimated to number 5,000. Ten leaves were 
selected at random within 10 feet of the ground and the number of 
adults and eggs was counted, the former numbering 5.3 per leaf 
on the average and the latter 160 per leaf. The tree was cut down 
and an examination of the topmost leaves showed an average of 186 
eggs per leaf; the adults, being disturbed, were not counted, but 
judging from the number of eggs present they evidently were more 
rather than less numerous than on leaves near the ground. Con- 
sidering the average .of 5.3 per leaf, however, the total number of 
adults on the tree would be estimated at 26,500, and at 160 eggs per 
leaf the number of eggs deposited would be estimated at 800,000. 
At the time of this observation about 50 per cent of the insects which 
overwintered on the citrus leaves had matured. The citrus white 
fly had been much reduced throughout the grove, in some sections 
by unexplained influences, in others by these influences and fumi- 
gation experiments combined, and on a few tangerine trees by a 
fungus parasite, red Aschersonia. The location of the umbrella tree 
did not seem to be a favorable one as regards opportunities for 
white-fly infestation, but examination showed the infestation to be 
at least 100 times greater, as regards the number of adults present, 
than on any citrus tree in the grove. There were, in fact, too few eggs 
deposited on the leaves of the citrus trees to allow of sufficient multi- 
plication of the white fly during the season to cause any blackening 
of foliage or fruit. 
CAPE JESSAMINE. 
The cape jessamine has long been recognized not only as a favorite 
food plant of the citrus white fly, but as especially important eco- 
nomically on account of its retaining its foliage throughout the year. 
From a statement by Kiley and Howard x concerning observations 
by Mr. H. G. Hubbard and statements by Dr. H. J. Webber, Dr. 
Montgomery, and others in the discussions on the citrus white fly at 
a meeting of the Florida State Horticultural Society, 2 it appears that 
the freezes of December, 1904, and February, 1905, which completely 
defoliated citrus trees when not especially protected, failed to defo- 
liate cape jessamines. In many localities it is probable that this food 
plant was responsible for the survival of the white fly at the time 
referred to. According to Dr. Sellards, 3 temperatures as low as 
1 Insect Life, vol. 7, p. 282. 
2 Proceedings of the Florida State Horticultural Society, 1896, p. 78. 
3 Press Bulletin 56, Florida Agricultural Experiment Station, p. 2. 
