Silkworm artificial diet

Suzy Gazlay smgazlay at
Fri Jan 19 20:47:15 EST 2001

I'm having some difficulty raising silkworms on an artificial diet and would
really appreciate insight, advice, experience -- anything that would help. I
am an elementary science curriculum writer who needs to figure this out if I
am to include silkworm investigations (which I would really like to do) in a
book which will be marketed nationally. If I put silkworm activities in the
book, I will need to have an alternative for teachers and kids in areas
where mulberry trees do not grow.
Last summer I tried using a commercial product, a powder which was mixed
with water and microwaved. First I had a viral problem with the eggs, and
the few larvae which emerged died in the first instar, except for one hardy
fellow in the leaf-eating group who munched his lonely way to adulthood. The
second batch of eggs was healthy, but the AD had a bacteria problem which
was not eliminated by the microwaving. I had half the larvae on the AD and
half on leaves, but when the AD batch started dying early on, I put everyone
on the leaves. Most who survived that rough start made it all the way
through the cycle and spun with no problem.
The company has since redone their AD and is marketing it as an already
mixed material about the consistency of play-dough. It has been autoclaved,
which should take care of the bacteria problem, right? One of my team
members has been using it in her classroom this winter. The first round went
well, although the silkworms were smaller than those we had both raised on
mulberry leaves. Her second batch, starting with eggs from the supplier,
started out just fine but in the last week or so has become a disaster. I
believe they were in their last or next-to-last instar when quite a few of
the larvae just stopped eating and died. Those that remain are having a very
difficult time spinning. She describes their silk as "gloppy" and says that
it is taking them many days to manage a cocoon. The threads are random and
disorganized, and the cocoon doesn't look like any of the cocoons she has
seen in the past.
This teacher has a lot of expertise with raising silkworms on leaf diet. She
really knows what she is doing, and she is very conscientious about their
care, so it isn't a problem of having the silkworms in a draft, or erratic
temperatures, which is what the person I spoke to at the AD company
attributed the problem to. Can anyone help me figure out what might be going
on? Could it have to do with the AD, or with the larvae, or both, or --??
Last week the company sent me three half-grown silkworms which I am feeding
the AD and watching closely. So far, so good, although they are not nearly
as vigorous as the ones I have raised on leaves.
In addition to my questions around this immediate problem, I would really
appreciate hearing from anyone who has experience with artificial silkworm
diet, including if you have a source or strategies which have been
successful for you.
Thank you!
Suzy Gazlay
AIMS Education Foundation
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