THE CITRUS WHITE FLY: FOOD PLANTS. 31 
was attached to the end of a branch covering new growth and from 
50 to 100 adults of A. citri were confined therein. Except in the case 
of the blackberry, in which no observation was made on the point, 
the adults were noted as resting contentedly and apparently feeding on 
the leaves for one or two days after being confined. In every case, 
however, all the adults were dead on the fourth day after confinement 
on the plants noted, although check lots of adults collected at the same 
time but confined on branches of citrus trees lived for a normal period. 
No eggs were deposited in any of the tests, although the check lots 
deposited eggs on the citrus leaves in a normal manner. 
Each of the five plants tested with the cage experiments have in 
addition been subjected to very careful examinations by the writers 
under such circumstances that the opportunities for infestation by 
the citrus white fly were at their best. In addition, particular atten- 
tion has been given to examinations of species of oaks (Quercus spp.) 
and bays (Persea spp.), guavas (Psidiwn spp.) and mulberries (Morus 
spp.), when located near, and in some cases with branches intermin- 
gling with infested citrus or other favorite food plants. 
Economic Significance of Food Plants, and Interrelationship Between Food 
Plants and Insects. 
Entomologists familiar with the present white-fly situation agree 
in their conclusion that a requisite for satisfactory control of this 
pest is proper attention to food plants other than citrus fruit trees. 
Mr. H. G. Hubbard, who was a well-known authority on orange 
insects, being a special agent of the Bureau of Entomology, was a 
strong advocate of destroying food plants of the white fly that were 
of no value. Dr. Sellards, formerly entomologist at the Florida Ex- 
periment Station, Dr. Berger, the present entomologist, Prof. P. H. 
Rolfs, director of the Florida Experiment Station, and the authors 
have each emphasized the importance of the relation of the various 
food plants to white-fly control. 
The following paragraph from the senior author's bulletin on the 
subject of fumigation for the citrus white fly x states in a general way 
the situation in this respect as viewed by entomologists who have 
investigated the white fly : 
The presence of food plants of the white fly other than citrus trees, in citrus fruit- 
growing sections, constitutes a serious menace and in itself often prevents successful 
results from remedial work. Fortunately the list of food plants is limited, and the 
greater number of those thus far recorded is subject to infestation only when located 
near or in the midst of heavily infested citrus groves. The food, plants which are of 
most importance in connection with the white-fly control are the chinaberry trees, 
privets, and cape jessamine, and these — except for the last, in certain sections where 
grown for commercial purposes — can be eradicated readily, or their infestation may 
be prevented where community interests precede those of the individual in controlling 
1 Bulletin 76, Bureau of Entomology, TJ. S. Department of Agriculture, pp. 9-10. 
