[pbs] Fungus gnats-- was --Looking for pic of the smaller Narcissus fly
Kelly O'Neill
kellyo at wetrock.com
Sun Mar 29 22:35:06 EDT 2009
> To clarify, Bacillus thuringiensis israelensis is used against Diptera
> larvae, most commonly mosquito larvae but also fungus gnat larvae.
...
> The form which kills caterpillars is different -- it's Bacillus
> thruingiensis kurstaki.
Jean is correct about the recommended subspecies of BT to use. I looked
into what seemed to work for me. I seem to have used the "wrong" ones. I
have used both:
Bonide® Thuricide®
Bacillus thuringiensis variety kurstaki.
and
Safer Brand Caterpillar Killer With BT -
Active Ingredient Bacillus Thuringiensis. Var. Kurstaki
> When mixed into the irrigation water for potted plants, one must
> continue using it for at least 3 weeks to disrupt the fungus gnat's
> life cycle.
The stuff is destroyed by sunlight and the kind I used is supposed to be
sprayed on the leaves. Thus, reapplication is needed above ground. My gut
feeling (an inside joke for those who know how Bt works) is that this stuff
lives longer than a week in the soil if watered in. I will go out on a limb with
very little (or no) evidence to say I think the stuff is happier in the soil than it
was in the bottle of concentrate and colonizes a never dry/frozen/extra
hot/poisoned soil. Whether you reapply or not, it still takes weeks to do the
job.
I should try the "right" stuff sometime. I still would not trust the israelensis
strains (Vectobac, Mosquito Dunks, Gnatrol, Bactimos, etc.) on my butterfly
larva foliage.
Kelly O'Neill
http://www.bigbubblers.com and
Big Bubble Magic(tm) at www.wetrock.com
and Wet Rock Gardens Flower Farm
2877 N 19th Street - Springfield, Oregon 97477
U-Pick and more at the farm (open 9 to 6, Sun,
Wed and Fri - from March thru Halloween)
kellyo at wetrock.com - http://www.wetrock.com
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