The Florida agriculturist. [volume] (DeLand, Fla.) 1878-1911, 1907-09-18
Dropping of Citrus Fruits.


ten by Prof. P. H. Rolls. 1t is too late
to do much good for this years crop.
But we advise you to keep it at hand
for reference next spring.
The dropping of citrus fruit in the
fall of the year may be due to one
of several Or all the causes working
together. The citrus grower, there
fore, must be able to diagnose the
difficulty before he can be able to de-
termine with certainty what remedy
to apply or if any is available.
Wither tip dropping has been de-
scrlbed a number of times in various
publications, in the agricultural papers
of the state, proceedings of the
Florida Horticultural Society, and
more fully in publications from the
United States Department of Agri-
culture and the Florida Experiment
Station. This trouble is not confined
to any portion of the citrus growing
area. Wherever this disease is pres
ent in citrus orchard it usually
causes the most severe trouble, the
fruit sometimes dropping to as much
as seventy-fve to ninety per cent. In
the aggregate it causes more loss from
dropping than all the others put to-
gether.
It may be readily and certainly dis
tinguished from other forms by the
fact that the trouble starts with IA
minute brown speck, gradually this
forms a depression and the size of
the speck increases. Sometimes a
number of these occur on a single
fruit, most frequently the fruit drops
before the brown specks have attain
ed the size of five cent piece. The
cause of the brown speck is due to an
attack of fungus, which is known
scientifically as Col1etotrichum gloe-
osporioides.
The remedy for this form of drop
ping is simply and singular1y effect
i've The fruit does not drop until
after it has been infected for some
time by the fungus, or until the spot
has attained considerable size, conse-
quently when the remedy is applied
it does not prove Immediately effect
i've, because those fruits which have
become inoculated later succumb to
the disease and the remedy merely
prevents other fruits from becoming
infected
AS soon as the citrus grower de-
tects any appreciable amount of drop
ping, he should at once examine the
fruit to find out whether it is caused
by the withertip fungus. If this be
the case he should at once spray with
a preparation of ammoniacal solution
of copper carbonate which is made as
follows:
Put three gallons of water in "a
wooden or an eanthen vessel, pour
three pints of ammonia (twenty-six
degrees b. into this, and stir it to
mix evenly Take eight ounces of
copper carbonate and shake it into
the ammonia water. stirring the liquid
for awhile If considerable part OF
the copper carbonate remains undis-
solved, the liquid may be left to set
the copper carbonate is dissolved,
more, of it should be added in the
manner previously described until
considerable amount remains undis-
solved; then it is set aside as stated
before. After the precipitate has Set
tied. use the clear blue liquid. The
undissolved copper carbonate may
then be treated with more ammonia
and water, fresh copper carbonate be-
ing added whenever the residue be-
comes less than an ounce. The So
luton should not be kept for more
than day or two, and when used
one gallon should be diluted with fif-
teen or twenty gallons of water
70