-DISEASES AND INSECT ENEMIES OF THE FIG. 179 
any conditions. To counteract this tendency to souring, the soil 
should be kept dry, though excessive dryness will also injure the figs. 
How increased moisture may gradually ruin a flg orchard has been 
observed several times. The writer once knew of several acres of fig 
trees which bore excellent and very sweet figs, the variety being the 
Marseillaise. These few acres were very profitable to the owner, but 
gradually the vicinity was settled; the soil became more saturated, 
because of extra irrigation introduced by new settlers, and as the 
trees grew older their roots struck deeper and more quickly through 
this added moisture. These figs gradually showed the effect of too 
much moisture, they became less sweet year after year, and more figs 
became sour. After the lapse of three years from the time they were 
in the height of profitable bearing the trees did not pay, and finally 
all were cut down as useless, except one or two around the house, 
which even there had become a nuisance on account of the dropping 
figs, which at last become sour, with only seldom a good or fair one. 
Small flies are often seen emerging from sour figs. These flies are, 
however, not the cause of the souring. They are simply vinegar flies, 
which, attracted by the sour juices, flock to the fig to there lay their 
eges and breed. They never visit healthy figs. The souring of the 
figs is greatly facilitated by their bursting open. As is well known 
in our fig districts, many figs burst open in the fall of the year or at 
the end of the summer. A few days after bursting the figs turn sour 
and become worthless for drying. The bursting open gives access 
to the interior of the fig to acetic bacteria, which cause the acid fer- 
mentation. As long as the eye was closed bacteria and fungi were 
kept out, and no fermentation could take place. There is no doubt 
that the principal function of the eye of the fig is to keep out bac- 
teria and insects, and the closed form of the fig receptacle is undoubt- 
edly effected by nature in order to prevent parasites from spoiling 
the sugary juice of the fig. Adriatics are especially apt to sour, but 
so far I have never found a sour fig which had not previously 
become cracked or split. The cracking open of the figs is due 
principally to moisture in soil and air. Figs will remain healthy on 
the trees until the advent of a rain storm or a fog. This increases 
the moisture in the air, which, again, causes the figs to swell from 
absorption of moisture. It is this swelling up which causes the figs 
to burst. Too much irrigation may have the same effect. Against 
the bursting on account of moisture in the air there is, so far as I can 
see, no remedy. 
SCALE. 
The fig tree in California has so far been very free from seale insects. 
In Europe, however, as well as in the Southern States, the fig trees are 
frequently attacked by seale. In the Mediterranean region the scale 
of the fig is the Chermes carice. It was mentioned by Cestoni in 
1733, and has been common since that time. It is a large scale, one- 
