The Florida agriculturist. [volume] (DeLand, Fla.) 1878-1911, 1880-09-22

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| 1t has not been part OF my work
to watch the spread of the cotton
worm over wide area, or 10 report
the extent of its depredations in this
county, but rather to study its
habits and life history, and to OBJ.
serve and study the enemies that
prey upon it, l have. therefore, con.
fined my observations to Mr..
Roberts plantation, and am not sure.
that the same conditions exist else
where. About the 1st of this month
there was here every indication that
anless a vigorous fight was made by
the application Of poisons clean
sweep would be made by the cater.
pillar during the month. Not only
were there scattering webs over the
entire acreage, but in several places
patches of five or six acres were en-
tirely ragged and the flies had there
appeared in great numbers. By the
9th OF the month the flies were seen
everywhere about the plantation,
and eggs were laid by millions in
every part of the cotton fields. AS
the eggs hatch i'll from three to four
days, and the worms, complete their
growth in about ten days thereafter,
there was OF course every prospect
that it left to itself the cotton would
be stripped by the middle OF August.
The worms, however, failed to make
their appearance in any numbers,
and there are now a few small
patches only where they can be
found. Now for the reason of this
unlocked tor change in the pro.
gramme. The eggs of the cater
pillar are laid upon the underside of
the lower leaves. When fresh they
are transparent in color, resembling
miniature emeralds, and so minute as
to be very difficult to detect. If
number Of these eggs are gathered
and kept few days in a tight box,
nearly all OF them will be found to
have turned black. The few that
remained green will have Matched,
and the young caterpillar that came
from them will be wandering about
the box. A day or two later these
black eggs also give birth, not To
young caterpillars, but from each OF
them emerges two little tour winged
flies. They spring from the cater.
pillar egg, perfect i'll every part, tull
grown, adult, ready to procreate and
reproduce their kind, but SO infini-
teslmal i'll size that without the aid
of microscope they are quite invis-
ible to most human eyes. This,
then, is their history. The caterpil-
lar egg from which they came had
been 'stung' by mother fly like
themselves. In 1t she laid two in
finitely small eggs. These Matched
maggots, which, by feeding upon the
contents of the caterpillar egg,
caused them to turn black. Having
devoured the contents OF the egg in
which they were born, the two little
maggots have reached their full size.
They then form their chrysalis, just
as the caterpillar itself does in its
web upon the cotton leaf, and, still
confined within the egg that has
sheltered and fed them, they change
in due time to perfect and adult flies,
eat their way out and fly off to pro-
create and sting more caterpillar
eggs. Having thus reproduced their
kind, their mission is ended, and
they die.
On this plantation about 80 per
cent Of all the caterpillar eggs laid
have been thus stung and destroyed.
The result is that The backbone of
this brood is broken, and as the cat.
erpillar has in its various other
stages many insect parasites, as well |
as enemies among the birds and
other animals, and as these become
more numerous as the season adj |
vances, the 10 per cent that do hatch |
are nearly all devoured by their foes
at one time or another, so that of
this remainder even not one in a |
1000 escapes and reaches maturity.
The little egg parasite has been
described by Professor Reilly, who
called it zrichogrananaa pretiosa. 1t
may be confidently asserted that
wherever it is doing such effective
work as it is now in this neighbor-
hood there need be no further fear of
damage by the caterpillar for this
season. II should be borne in mind,
however, that not every year will
the planter have the aid of such an
effective ally, and the best advice
that can be given him is to store up