34 BULLETIN 640, TJ. S. DEPARTMENT OP AGRICULTURE. 
VALUE OF ELIMINATING HOST VEGETATION. 
In Honolulu many mango and orange trees were either cut down 
or severely trimmed, but those cut formed too small a percentage of 
the entire host vegetation to serve a practical purpose. The only 
places where the elimination of host vegetation yielded favorable 
results were about banana and pineapple plantations where the work 
was done in accordance with the regulations of the Federal Horti- 
cultural Board. In these instances the destruction of vegetation did 
not eliminate the adult flies, for these came in from surrounding 
areas. It did, however, lessen the danger of immature stages becoming 
attached to the packing material of bananas and pineapples shipped 
to the mainland. 
Should the Mediterranean fruit fly ever become established in 
California or the Southern States, however, where there is no such 
wealth of native host fruits and where climatic conditions will prove 
an important factor in control, the elimination of host vegetation 
will play a most valuable part in remedial measures. In Algeria the 
infestation of oranges greatly increased after such crops as peaches 
and persimmons were grown. These fruits furnished food for the 
fly during the summer and early fall months, which were for the fly 
starvation months previous to the cultivation of these crops. Aided 
by these summer crops, the fruit fly was able to increase greatly, 
so that when the orange crop began to ripen during the fall and winter 
months the pest could attack it with increased force. In Bermuda 
the elimination of a comparatively few host trees, numerically speak- 
ing, would mean the elimination of breeding places for considerable 
areas. The destruction of unnecessary and valueless host trees will 
not only restrict the breeding ground, but will often so break up the 
sequence of ripening hosts that many adult flies will die while 
attempting to bridge the starvation periods when no fruits can be 
found for egg laying. 
DESTRUCTION OF INFESTED FRUITS AND SPRAYING. 
The destruction of infested fruits and spraying are remedial meas- 
ures that should go hand in hand. In Honolulu they have not given 
satisfactory results for reasons beyond the control of man, as set 
forth on pages 24 to 33. Nevertheless, they can be made successful 
in commercial orchards, if applied with intelligence and persistence 
throughout a neighborhood. One indifferent neighbor can spoil the 
work carried on in surrounding orchards. A community of growers 
must determine in what crop their interests are centered and im- 
partially eliminate nonessential fruits. Then, and, as a rule, not 
until then, will labor spent on the destruction of infested fruits and 
