bacillus thuringiensis shelf life

Paul Cherubini paulcher at
Thu Jun 25 15:02:12 EDT 1998

Dear S,

I must be dense, but I don't get what you are trying to say.
You've said Bt is  a "destroyer of butterflies of all types, bar none"
"highly destructive" "persists in the soil", "devastates ecology".

The experienced users we have heard from today and numerous farmers I
know say it's a weak moth larva killer at best,  affects only the early
instars, has a short storage life and is degraded rapidly by exposure to
sunlight following outdoor applications.

Is your point that moth larvae are somehow immune to Bt whereas
butterfly larvae are somehow extremely susceptible?  If it persists in
the soil, what harm does it do there to butterfly and moth caterpillars?

To understand your point from a practical example,  are you saying that
you know for sure that if I sprayed my  backyard milkweed patches today
with Bt , the monarch butterfly caterpillars I have would be "destroyed"
and the yard soil would be so contaminated that monarch caterpillar
survival would not be possible for years?

Forgive me if this comes across as being sarcastic. The subject of
pesticides is one of those touchy, polarizing issues.

Paul Cherubini
paulcher at

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