STATE PL.AIT BOARD
January 1944 E-611
United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
CLOSED FIGS IN RELATION TO INSECT ATTACK AND DISEASE INFECTION
By Perez Simmons and Charles K. Fisher,
Division of Fruit Insect Investigations
The purpose of this brief discussion is to bring together cer-
tain facts about the protection afforded by tight eyes in figs against
invasion by insects and the various organisms that cause spoilage, and
consequent loss to growers, which in some seasons is a serious matter.
Producers of figs have been aware of most of these facts in a general
way, and the present report can only strengthen the evidence that a
valuable improvement would result if the character of tight eyes could
The term "closed figs" as used herein refers to figs which are
closed at the eye by overlapping scales so that there is no visible
opening, or only a minute opening, to the interior. Figs which nre
"self-sealed" with hardened syrup are not considered. This type of
sealing has been found to be of little value since it appears to be
a product of seasonal conditions.
Experimental sealing of the eyes of small green figs by repre-
sentatives of the California Agricultural Experiment Station, the
Bureau of Entomology and Plant Quarantine of the United States De-
partment of Agriculture, and others has shown that figs which are
kept sealed during development are resistant to infestation by in-
sects and to infection by diseases. Sealing figs on a commercial
scale does not appear practical, although it can be done by spraying.
To obtain a cross-sectional record, figs of the Adriatic and
Calimyrnyma varieties were examined by the writers at a storage plant
after the fruit had been graded into 6 sizes- -Standard, Choice,
Extra Choice, Fancy, Extra Fancy, and Jumbo. The figs had not been
sorted after receipt from growers. In all grades there were figs of
all degrees of closure, from those completely closed to those wide
open. From each grade all the closed figs and those with the M:ost
widely open eyes were removed. There were no records of the places
of origin of the figs, which doubtless were representative of a num-
ber of orchards. About 38,000 figs were examined, as shown in table
1, which follows, xamunples of figs of both varieties, of all size
grades, and with closed and open eyes are shown in figures 1 and 2.
These examples are not necessarily typical, but they represent the
run of fruit in the lots examined. For purposes of photography the
figs were flattened.
Table 1.- -Occurrence of closed figs in random samples.
Size Number of Closed figs, Number of Closed figs,
grade figs examined percent figs examined percent
Standard 3,202 51.9 4,675 10.0
Choice 2,840 51.4 2,685 7.7
Extra Choice 5,946 15.7 5,866 7.5
Fancy 5,597 10.4 2,841 7.7
Extra Fancy 5,085 8.8 2,575 7.0
Jumbo 2,824 15.3 2,268 5.5
The figures in table 1 show that closed figs were generally dis-
tributed among all size grades of both varieties, although more common
in the smaller figs, which suggests that it is normal for such figs to
be produced as a part of many crops. The writers do not know whether
or not there are trees or branches which produce them to the exclusion
of open figs. The records for the Calimyrna variety show that these
figs, which require caprification, do not need open eyes at any stage
of development; in fact, Calimyrna figs usually are closed by scales
at the time the caprifying insect forces its way into the small green
Among the Extra Choice grade of Adriatic figs were a few dozen
with eyes that were folded or crimped, as illustrated in figure 5.
These were well closed, and there is a possibility that they represent
a sport (mutation) which could be reproduced by grafting or by rooted
Examination of 100 closed and 100 open figs from each grade of
the 2 varieties showed clearly the protection afforded by closed eyes.
Although some individual figs contained more than 1 type of material
causing spoilage- -for example, insects and souring- -each unsound fig
has been recorded only once, insects taking precedence over diseases,
and diseases over dirt, in accordance with established practice.
These results are given in table 2, which follows.
The figs from which the data were obtained were of the crop of
1937. They are, therefore, not necessarily representative of deliveries
of figs of more recent years, but the figures do illustrate the improve-
ments in quality that accompany the closed-eye character.
Table 2.- -Extent of spoilage in Adriatic and Calimyrna
figs having closed and open eyes, taken from the
same storage boxes
Nature of spoilage Percent of spoilage in- ..
Adriatic figs Calimyrna figs..
Open Closed Open Closed..
Dried-fruit beetle 1.0 0.2 1.2 0.2
Raisin moth 2.5 .8 1.7 .2
Vinegar fly .5 0 0 0
Miscellaneous 0 0 .2 0
Smut and mold 9.7 .5 11.7 1.0
Souring 5.5 .8 5.5 .3
Endosepsis 0 0 2.0 .2
Dirt (inside) 5.5 0 .8 0
Total 22.1 2.5 20.9 1.9
The percentage of spoilage was consistently greater in figs of
the larger sizes, the eyes of which, on the average, are larger. The
percentages in the open Adriatic figs ranged from 6 for the Standard
size to 59 for the Jumbo; for the Calimyrna the range was from 7 to
The following observations may be made from table 2:
(1) The closed dried figs were remarkably free front spoilaCe,
which would not have been the case had the figs been open at .ny time
during growth and ripening.
(2) Closed figs were protected even after f-dl1ing to the gr-und
and during drying and storage. This is shown by the figures for infes-
tation by the raisin moth, an insect which seliora infests figs on t: ..
During September 1943 the records given above were supplemented
by counts of closed figs on the ground in orchards. A 50-fig random
sample was examined under 20 trees in each of 14 orchards, a total of
14,000, half of the Adriatic variety and half of the Calimyrna. The
plantings were in Tulare, Fresno, and Merced Counties. Closed figs
were found in all samples of the Adriatic; the average percentage of
closed figs was 17.5. Figs of the Calimyrna variety were closed to
an average extent of only 1.5 percent.
The indications are that the closed-eye variation occurs gener-
ally but that there are differences in this respect between localities
and seasons as well as between varieties. The existence of trees or
branches bearing closed figs exclusively and year after year is at
present a matter for speculation; yet the benefits to the industry
through reduction in spoilage would, in time, be great if trees or
branches bearing such superior fruit could be found and grafting wood
were widely distributed. Growers might well be on the lookout for
trees or single branches bearing figs that are closed when dry.
STATE PLANT ROADn
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UNIVERSITY OF FLORIDA
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