78 
FLORIDA STATE HORTICULTURAL SOCIETY. 
the 'whitehy larvae can be readily found. 
Later, say in three or four weeks, inspect 
the grove and spray all the trees not pre¬ 
viously sprayed and which now show the 
presence of whitefly. In another three or 
four weeks inspect again and spray. Each 
tree should be considered individually and 
treated accordingly. Any trees not show¬ 
ing a good start of fungus in three to six 
weeks should be sprayed again, wholly or 
in part. This kind of procedure should be 
continued from year to year, and the pre¬ 
diction is made that in a comparatively 
few years, when the citrus growing sec¬ 
tions of the State have in this manner been 
thoroughly saturated with the fungi, there 
will be no whitefly problem. 
I have stated above that the fungi in 
question can thrive only upon the whitefly 
larvae and pupae and this is probably true 
in nature. In the laboratory, however. 
Professor H. S. Fawcett has been success¬ 
ful in growing the Yellow and Red As- 
chersonias, and to produce spores, upon 
several of the media generally used for 
such work. There is but little doubt that 
the Brown Fungus can be cultivated • on 
the same media. This opens up the pos¬ 
sibility of producing spores of the fungi in 
the laboratory for use upon trees. But 
as an abundance can generally be obtained 
from infected groves it is not likely that 
we shall very soon be compelled to depend 
upon artificial means for a supply. The 
fact, however, that a fungus can be cul¬ 
tivated artificially gives the scientific in¬ 
vestigator greater opportunity for careful 
and varied experiments and observations 
that may eventually lead to broad scien¬ 
tific principles of practical value. 
I wish to state again that if the first 
attempt at introducing the fungus fails 
to produce a good start in a grove, or in 
individual trees of a grove, a second at¬ 
tempt .should be made and a third one if 
necessary. This kind of spraying is much 
cheaper (and I believe spraying on the 
spores is preferable to pinning on the 
leaves; but both methods can be used) 
than spraying with insecticides, and is 
perfectly harmless to the trees. This 
point, Lirthermore, should not be lost 
sight of, that the increase of the fungus in 
a tree (other things being equal) is in 
the same proportion that we succeed in 
starting it in that tree. Thus, if we suc¬ 
ceed in starting loo pustules of fungus in 
one tree an'd 300 in another, it will be ev¬ 
ident that the spread of the fungus in the 
last tree \Vill be three times as rapid as in 
the first one, and hence the importance 
of making .as *good a start of fungus as 
possible by repeated sprayings. 
Attention should also be directed to the 
fact, that for subsequent sprayings, fun¬ 
gus from the trees previously treated may 
be used, provided it is sufficiently develop¬ 
ed. This will be evident as the pustules 
increase in size and become a bright scar¬ 
let red in the Red Aschersonia or a bright 
yellow in the Yellow Aschersonia. 
BY PINNING ON LEAVES. 
To introduce the fungus by pinning on 
leaves I would suggest that from one to a 
dozen or more well infected leaves be 
pinned to a tree. The number will be de¬ 
termined by the amount available. At 
Leesburg 12 leaves per tree were used. 
Each infected leaf should be pinned to the 
under surface of the leaf on the tree, with 
its under surface down, that having been 
its position before it w'as removed from the 
tree and is in closest keeping with nature. 
The infected leaves might be pinned with 
the infected (or under) side against the 
under side of the leaves on the tree, and I 
have obtained good results in this way, 
