FLORIDA STATE HORTICULTURAL SOCIETY 
71 
We will have our problems to work out 
as we go along and in many cases can 
profit by the experiences of the Avocado 
growers in this section. If the industry 
develops in Lee County as I anticipate it 
will, this section should contribute some¬ 
thing of interest to the Avocado industry 
in the future. I believe that by close co- * 
operation and through a free exchange of 
ideas on the subject, much can be done 
to rapidly build up a permanent and 
healthy industry in the growing of sub¬ 
tropical fruits. We have a section of 
country peculiarly suited for such devel¬ 
opment, so why not take advantage of 
the opportunity. 
But to return to the subject I am to 
discuss, “Spraying for Avocado Dis¬ 
eases/’ 
There are three diseases of the Avocado 
fruit that might prove to be troublesome 
factors in the production of Avocados for 
commercial purposes. These are, Black 
Spot, Avocado Blotch and Avocado Scab. 
They are all fungus diseases and they 
were described and treated in the Annual 
Report of this Society for last year. 
Black Spot and Blotch affect the fruit 
as it approaches maturity, making a 
worthless fruit for shipping purposes, 
and both of these diseases may be fore¬ 
runners of rapid decay. These two dis¬ 
eases are more common on the seedling 
varieties at the present time, however, 
Black Spot has been observed to occur on 
some of the budded varieties to some ex¬ 
tent. Avocado Scab occurs on both seed¬ 
ling and budded varieties and this disease 
attacks the fruit during the early stages 
of its development. Scab does not affect 
the interior of the fruit but it mars the 
outward appearance of mature fruits and 
severe attacks may cause a heavy shed¬ 
ding of young fruits or a stunted and 
misshapen growth. 
As plant pathologist of the Florida Ag¬ 
ricultural Experiment Station, I had 
made some investigation of these diseases 
for two or three seasons past to determine 
their causes and find some means of con¬ 
trol. The preliminary experiments that 
we previously tried had shown little ef¬ 
fect in controlling Black Spot or Blotch. 
In the spring of 1920 a definite plan of 
spraying was outlined and carried 
through the season, which took into con¬ 
sideration the control of each of these dis¬ 
eases. Our plan was to begin about the 
middle of the bloom period and to spray 
at monthly intervals over a period in 
which the fruits appeared to be more sus¬ 
ceptible to these diseases. Bordeaux 
Mixture 3-3-50 or its equivalent was used 
in the first applications and the 4-4-50 
formula in the last applications. The 
spraying was done with a power sprayer 
and spray guns. The object of this ex¬ 
periment was to determine the number of 
applications of Bordeaux Mixture neces¬ 
sary to control these diseases and the time 
they should be applied to be effective. 
The results obtained were very encour¬ 
aging and I think demonstrate that each 
of these diseases can be controlled by 
proper spraying. 
In the sprayings for Black Spot and 
Blotch thirty-six seedling Avocado trees 
were selected in a grove where the fruit 
had spotted badly during the past few 
seasons from these two diseases. The 
trees were large and from fifteen to 
eighteen years old. The trees were di- 
