Florida Agricultural Experiment Station


71). Split fruits usually drop within a short time. This type of
splitting occurs in apparently healthy fruit and is to be dis-
tinguished from that which ordinarily occurs in fruit borne on
trees affected by exanthema, since, in the latter case, the fruits
that split usually are undersized and split irregularly, and fre-
quently at right angles to the axis.

 CAUSE OF FRUIT-SPLITTING
 The factors involved in fruit-splitting are very imperfectly
understood. Irregularity of water supply is believed to produce
a greater fluctuation in the turgor of the pulp of the fruit than
in the rind. In many instances a large amount of splitting oc-
curs when heavy rainfall follows a period of drought and it is
generally considered that the pulp takes up water faster than the
rind can expand. In 1926, however, this explanation of split-
ting received a decided setback since the rainfall was so well dis-
tributed in most sections that the soil was considered to be in a
moist condition throughout the summer and fall. Fruit-split-
ting may possibly be related to conditions that increase the con-
tent of pentosans and gums within the fruit, since any increase
in these substances enormously increases the water-absorbing
capacity of the tissues so that they may swell so rapidly by the
absorption of water that the rind cannot withstand the internal
pressure.
 The highest percentage of splitting in any given variety ap-
pears to occur on the light, sandy soils deficient in humus, es-
pecially those on which very little or no cover crop is grown,
while the lowest percentage, as a rule, occurs on the heavier soils
with a good content of organic matter. The least amount of
fruit-splitting occurs as the optimum conditions for citrus cul-
ture are approached.
 According to the observations of Camp in the fall of 1926,
the fruit on the younger trees of all varieties observed was more
severely affected by splitting than that on trees from 10 to 15
years old. These observations also showed that there was a wide
variation in the amount of split fruit in adjacent groves of the
same age and variety and apparently on the same type of soil,
which indicated that more than mere weather factors were in-
volved. It would appear from this that some of the present grove
practices are important contributing factors in the development
of splitting. While it is quite likely that fruit-splitting is but one