CULT:Insect Predators of Borer--Circa 1928

Greetings:

I have found a scrap of information about possible natural insect predators
of borer which I share without comment. Perhaps someone will be able to  tell
us tell us what further experiments were conducted in this area, or discuss
the possible utility of the information.

>From the Bulletin of the American Iris Society, Number 26, January 1928, p.
20 ff, "Science Series No.1--The Iris Borer", by Harry F. Dietz. (page 23f).

"Just how effective parasites are in the control of iris borer is not
definitely known. Two parasites have been reared from caterpillers collected
at Indianapolis. These are Apenteles militaris Walsh and Amblytekes jucundus
Brulle. Both are hymenoptera belonging to the superfamily Ichneumonoidea.
both are recorded as parasites of the army worm Cirphis
(Leucania--Heliophila) unipuncta. 

Apanteles militaris is a small blackish parasite about two to three mm. long
and individually inconspicuous. However, since a large number hatch from a
single worm this species ought to be quite effective. The adult female
Apanteles lays her eggs directly into the body of the caterpiller. These eggs
hatch into grubs which feed on the vital organs of the caterpiller. These
grubs become full grown just before the caterpiller is ready to transform
into the pupal stage. Then these grubs bore through the body wall of the
caterpiller and spin elliptical silken cocoons. These whiteish cocoons which
are tinged with brown are massed in the tunnels of the borer beside or near
the shriveled remains of the victim.

Amblyteles jucundus is much larger and more conspicuous than Apanteles. It
measures between eleven and fourteen mm. in length. It is deep reddish brown
to blackish in general color with the second segment of the abdomen yellowish
and with the third, fourth and sixth banded with white. To the layman it
resembles a small wasp. At just what stage in the life cycle of the borer it
is attacked by the adult Amblyteles is not known. How many eggs are laid by a
single parasite on each catrpiller has not yet been determined. If this
presumption is correct then the caterpiller is not prevented from changing to
a pupa and at least part of the development of the Amblyteles grub takes
place in the pupa of the borer. It is from the root borer pupa that the adult
parasite emerges through a large hole that it tears in the anterior end of
its victim. 
[....]
Iris borer belongs to the family Noctuidae which included the cutworms and
the 
armyworms. It would not be surprising if a number of other parasites, known
to attack cutworms and armyworms were sooner or later bred from iris borer.
It is possible that in areas where iris borer has been found only
occasionally it is held in check by some of these natural enemies.[...]

Anner Whitehead, Richmond, VA 
Henry Hall henryanner@aol.com
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