FLORIDA STATE HORTICULTURAL SOCIETY. 
A NEW THEORY FOR REPELLING THE WHITEFLY. 
Chas. R. Hardy. 
Mr. President , Ladies and Gentlemen : 
The most serious menace to the citrus 
fruit industry of Florida appears to be 
the destructive effects of the whitefly. Al¬ 
most every section of the State, except 
possibly far down on the East Coast, has 
suffered from visitations of the pest and 
considerable time and money have been 
spent in combating the inroads made by 
i he insect in the groves of the orange 
growers. 
At present three methods of extermina¬ 
tion are being used with more or less suc¬ 
cess, viz: fungi, fumigation, and spraying 
with various insecticides. However suc¬ 
cessful any of these methods may be in 
cleaning up a grove they are but tempo¬ 
rary expedients at best, and must be con¬ 
tinued indefinitely, thereby adding consid¬ 
erably to the expense of growing a crop 
of fruit. The theory that I am about to 
suggest, and which I am firmly convinced 
will be the only positive and permanent 
means for successfully combating the 
whitefly differs radically from all these. 
It is simply to make the orange tree im¬ 
mune to the attacks of this insect and rea¬ 
soning from analogy, I see no reason why 
t may not be done. 
Several years ago the wheat growing 
mdustry of England was all but destroy¬ 
ed because of the rust that attacked the 
wheat fields. After experimenting with 
n large number of varieties of wheat 
which had been gathered from all parts 
of the world, one variety was discovered 
that offered great resistance to the at¬ 
tacks of the disease. This variety was 
proved to be immune and specimens grow¬ 
ing among plants of affected kinds inva¬ 
riably repelled the rust. This was an im¬ 
portant discovery, but this quality was 
about all that could commend this variety 
to the growers. In other respects it was a 
very poor and unsatisfactory grain. How¬ 
ever, by crossing it with other varieties of 
more vigorous growth and larger heads, a 
strain was subsequently built up that ex¬ 
hibited all the best qualities desired in a 
good wheat and, in addition, it was also 
made immune to the rust fungus. 
It is a well known fact to experimen¬ 
tal botanists that individual qualities in¬ 
herent in any species may be imparted to 
kindred species by cross fertilization and 
that varieties of plants may be success¬ 
fully built up that will exhibit all the de¬ 
sirable features that may be inherent in 
the parent plants. How then may this 
principle be applied in producing an or¬ 
ange that may be immune to the whitefly ? 
Two methods at once suggest them¬ 
selves. 
First: bring together every species and 
variety of citrus fruits from every coun¬ 
try of the globe where they may be found 
and subject them all to experiment. Place 
the whitefly among them and see if any 
trees exhibit repellant qualities to the at¬ 
tacks of the insect. If among them one 
