FLORIDA STATE HORTICULTURAL SOCIETY 
119 
times in the grove. Under average con¬ 
ditions, and with an average amount of 
growth, no injury is likely to result. But 
under conditions favorable to dieback, and 
with a very rank growth of the legumes, 
the disease may appear. I have seen nu¬ 
merous groves where a rank growth of 
begganveed was coincident with an active 
dieback condition of the trees. 
Excessive cultivation, and deep culti¬ 
vation at the wrong season of the year, 
are factors that are favorable to the dis¬ 
ease. I recently saw a grove on high pine 
land, in the central portion of the State, 
which was excessively cultivated one year 
ago this spring in order to rid it of a sod 
of Bermuda grass. The prompt develop¬ 
ment of dieback during the summer and 
fall, with an absence of other factors 
known to be favorable to the disease, in¬ 
dicated a relationship. Many similar ex¬ 
amples may be cited. Plowing the grove 
during the late spring, or during the sum¬ 
mer, is favorable to the disease and is a 
practice to be avoided. 
Many severely affected groves, particu¬ 
larly on the high pine lands, have been in¬ 
duced to grow out of the disease by the 
“let alone” policy of non-cultivation and 
light feeding. 
The prevention of the disease by the 
prevention of the conditions favorable to 
the disease is necessarily a slow method. 
It usually requires from one to two years 
for the average trees to entirely recover. 
When there are indications of the fruit 
becoming marked, or there is reason to 
believe from the history of the grove that 
it will become marked, spraying the trees 
with Bordeaux mixture will often save 
the particular crop of fruit and be an aid 
in ridding the tree of the disease. 
Some unpublished data of experiments 
conducted by Prof. Rolfs of the Experi¬ 
ment Station showed very positive bene¬ 
fits from the use of 3-3-50 Bordeaux mix¬ 
ture in preventing the marking of the 
fruit, and in controlling the dieback. 
In using Bordeaux, it should be applied 
first when the fruit is less than walnut size, 
and again about one month to six weeks 
later. These times would ordinarily be in 
May and June. The strength to use is 
3-3-50. In applying it, the spray should 
be directed from above downward in such 
a manner that only the fruit and the up¬ 
per surfaces of the leaves catch it. The 
spray should be kept from the stems and 
the under surfaces of the leaves as much 
as possible. 
As is well known, the Bordeaux mix¬ 
ture kills the friendly fungi that hold the 
whiteflies and purple scale in check. Un¬ 
less precautions are taken, the purple scale 
is likely to increase in such numbers as to 
do much damage. These precautions 
should consist: (1) in so directing the 
spray as to protect the stems and under 
surfaces of the leaves as much as possible 
(this leaves a stock supply of the friendly 
fungi to replace those killed by the 
spray) ; and (2) inspecting the trees fre¬ 
quently for any development of the scale. 
If they are seen to be increasing in num¬ 
bers, spray at once either -with whale-oil 
soap or with an oil spray. 
If any spraying is to be done for the 
whitefly, it is a good plan to use the Bor¬ 
deaux mixture two or three weeks before. 
The oil spray used for the fly will thus 
serve the dual purpose of holding both 
