The Delta independent., 1910-09-09
EGG PARASITES OF COD
DLlNG MOTH AT WORK
Little Fellows Studied In Numerous
Delta County Orchards by
Professors Weldon and
Herrick.

Recently number of Delta county
orchards were visited, and a care
ful search was made by Mr.. Herrick
and myself for the tiny parasite that
develops within the egg of the cod
ding moth and instead of the de-
structive apple worm Matching from
the egg, tiny light-yellow colored,
four-winged insect emerges there
from and searches for other eggs to
devour. In practically every orchard
visited, a number of eggs containing
the parasites were found, proving
conclusively that this valuable insect
which has recently become so abun-
dant in Mesa county is doing its
good work in Delta county also.
This parasite is not new insect,
having been known for a number of
years as an egg parasite. The first
time that it was found in Colorado,
was about four years ago when Prof
E. P. Taylor, who then was ento-'
mologist of the fruit investigation
station at Grand Junction found
1t destroying few coddling moth
eggs in the Grand valley. Since
that time they have probably been in
creasing until at the present time
they are so numerous that a care
full search for eggs of the coddling
moth the past month, has indicat-
ed that at least so per cent have
been destroyed by parasites during
that time
This little enemy of the coddling
rfb fs t4 ha let
as trichogramm pretiosa. While
not a bee, it is quite closely related
TO them, belonging to the order Hy-
menopetra an order which contains
the bees. wasps, ants and parasite
being classed with the latter.
The life history as far as is known
is quite interesting The female de-
posits a number of eggs within the
coddling moth egg, Gtself not larg-
er than the head of an ordinary pin)
these eggs hatch into larvae which
devour the contents of the coddling
moth egg. When mature. the para
sites cut little circular holes in the
surface of the egg upon which they
have been feeding. and emerge as
perfectly formed four-winged in
sects. | have watched with my
pocket lens, the little parasites de-
posit their eggs Within the cod
ding moth egg, and to me it was
an extremely interesting sight. The
little parasite moves slowly about
over the surface of the newly laid
coddling moth egg for time, sud
denly she thrusts a tiny needle-like
ovipositor into the egg of the cod
ding moth, and in a few seconds
ed with the naked eye, or even with
hand lens, is deposited within.
Again she feels about over the sur
face of the egg and when a suit
able point is found for insertion
of the ovipositor. the operation
is repeated. l have watched one
little parasite deposit five of these
eggs in one coddling moth egg.
Just where and how this little
parasite spends the winter is not
known, and the working out of
this part of its life's history will
be an interesting problem for some
entomologist
The detection of the work of the
parasite in the orchards is COM
paratively simple matter. Eggs of
the coddling moth upon which they
have been feeding soon become
blackened. Normally the egg of the
coddling moth is never black. When
first deposited they are creamy white
1 in color. and in about three days
reddish ring is distinctively seen
close to the margin of the egg, and
| is the outline of the little coddling
moth larvae developing within Just
before Matching, which usually takes
tiny black spot may be seen near one
side of the egg. This dark colored
spot is the head of the larva. When
the eggs are blackened over the en-
tire surface, or nearly so. then there
is something wrong with them and
in all cases which have come under
my observation the blackening has
been due to the parasites. l have
collected hundreds of these black
ened eggs, and have been success
tul in rearing a great many para
sites from them.
am often asked how the para
that question cannot be directly ans
wered. It is probable that they have
occurred, but not abundantly. ever
since apple growing has been going
on in the valley. The multiplication
of any insect pest favors its de-
struction by parasites, for the null
tiplication of the parasites is depend
ent largely upon their food supply.
The eggs of the coddling moth have