bacillus thuringiensis shelf life

Semjase semjase at
Thu Jun 25 20:41:50 EDT 1998


The stuff is a spore forming organism, very stable when in that form and when
introduced into the soil.  You are correct he may be having a delivery problem
while at the same time devastating the ecology.

S.><HTML><PRE>Subject: Re: bacillus thuringiensis shelf life
>From: conlan at ADNC.COM (Chris Conlan)
>Date: Thu, Jun 25, 1998 03:00 EDT
>Message-id: <v01530501b1b79bcb3dbd@[]>
>        Contrary to an earlier response to your post this stuff does not
>last forever and it doesn't kill everything.  The shelf life also depends
>on the type of formulation and how it is stored.  Powder and granule
>formulations tend to last longer than liquids.  I'm going to assume your
>stuff is a liquid.  If it was stored under cool conditions or near room
>temp it will probably be OK for at least one year and maybe even 2 years.
>If you are like most people and it was left in a hot garage or storage shed
>for the summer it may not have much left in it.  It's usually best to get a
>fresh batch every year.  Once you dilute it into water it probably won't
>last long.  Keeping it dark and cool will help lengthen the shelf life.
>Sunlight is murder on the stuff and once applied the sun usually causes
>most of it to break down within a few days.
>        B.t.'s also come in a variety of strains and while it may be that
>your sample is old and weak it also may just not be a particularly active
>strain for Squash Vine Borer.  I honestly don't remember whether the
>kurstaki strain is good for vine borers (it probably is but it's been
>awhile!).  You also may just be experiencing a delivery problem.  Since the
>vine borers are inside the stems and the B.t. must be consumed to be
>activated you just might not be getting the toxin to your subjects in a
>high enough dose to work (even if injected).  Also, B.t.'s tend to work
>much better on the early instars.  I hope this helps a little.  Let me know
>if you have any other questions and I'll do what I can to answer.
>conlan at

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