86 
FLORIDA STATE HORTICULTURAL SOCIETY. 
show the lantern slides on fumigation 
prepared by Mr. Yothers. 
(.Manuscript read not presented for 
publication as it will shortly appear in 
bulletin form.) 
Discussion following reading and lan¬ 
tern slides. 
Mr. Porcher: I would like to ask if 
anyone present has had any practical re¬ 
sults from fumigation. 
Mr. Skinner: I fumigated a five acre 
grove and killed 98 per cent of the fly, 
and also killed all the crop for that year. 
My neighbor did not fumigate, and the 
next year all the flies from his grove— 
or so it seems to me—-came over to my 
place and camped on my ground. I 
would not fumigate again unless every¬ 
one in the surrounding country did. It 
certainly kills the flies and scales, how¬ 
ever. The Chases have two groves which 
they fumigated and absolutely kept the 
fly in check. They absolutely stamped it 
out. On their budded trees they have an 
elegant crop. 
Dr. Back: I do not consider that fu¬ 
migation is advisable in a grove surround¬ 
ed by other infested groves unless every¬ 
one fumigates at the same time. Mr. 
Temple’s “Baby” grove at Winter Park 
is a good example of the uselessness of 
fumigation when such conditions exist. 
And for this reason, also, the fumigation 
in the Earle and Sadler groves at Tan¬ 
gerine will be of no practical value in con¬ 
trolling the fly. On the other hand, the 
Friar grove at Victoria is an example of 
the good results that can be obtained by 
fumigation in an isolated grove. 
Mr. Skinner: I might add, however, 
that the grove lost last year’s crop, but 
it looks as though the trees will have 
enough this year for both years. I never 
in all my life saw trees have such a fine 
crop. The fumigation killed all the ene¬ 
mies the trees had. 
Dr. Back: The fact that Mr. Skin¬ 
ner’s grove did not bear a heavy crop the 
season following fumigation does not 
necessarily prove that fumigation was re¬ 
sponsible for the poor crop. Fumigation 
sometimes receives credit for a poor crop 
when in reality it merely precedes what 
would under normal conditions be an off- 
bearing year. Our experience at St. Au¬ 
gustine and Victoria alone demonstrates 
that a heavy crop of fruit may set the 
spring following fumigation. And those 
who have noted the crop on the trees fu¬ 
migated at Tangerine last winter, know 
that there is as much fruit on the fumi¬ 
gated as on the unfumigated trees. 
Mr.—Even when you kill ninety- 
nine per cent of the fly you don’t always 
have good results, do you? 
Dr. Back: It is a very easy matter 
to fumigate and kill from 95 per cent, to 
99.5 per cent, of the fly. While this 
seems like reducing the fly to the point of 
extinction, as a matter of fact, in a grove 
where there are from 150 to 200 living 
pupae per leaf, even if as many as 99.6 
per cent, are killed, a large number of 
flies are left. If you kill 99 per cent, you 
have left at least as many flies as you 
have leaves, and by the following fall 
they will have increased to an astonish¬ 
ing extent. The length of time one fu¬ 
migation will remain effective depends 
largely on the numerical abundance of the 
fly represented by the percentage that es¬ 
capes fumigation. In other words, one 
