Bacillus thuringiensis kurstaki (Btk) is used against caterpillars.

But mosquito dunks are Bacillus thuringiensis israelensis (Bti) and it's used against mosquito larvae.

In other words, the two products are different.

Ok, that clears up part of it.

Are these products concidered compatible to organic practices?

In most cases, yes. Some of the newest formulations of Bt do not meet the 'Certified Organic' criteria because of additives, etc. Commercial growers producing products labeled 'certified organic' always need to be careful of label restrictions for legal reasons. But any of the products that are available to the average homeowner are considered organic by any standards.

Thank you rhizo,
I'm not really worried about being certified organic but this was a point of interest to me. I'm just trying to learn as much as I can.

This is such a good product for the organic gardener. As the previous posts states there are many types...for caterpillar, mosquitoes, etc. Fear not, this is a good product and at the heart of my organic arsenal for caterpillar that would wipe out my cruciferae, nightshade, and cucurbitaceae, crops. In the last 30 years I have heard of 1 person having a reaction to the additives in a product. This is so much not a don't loose sleep issue...Is the air safe, is the water safe...that is the realm you're worrying in. I give this a 100% good for the organic gardnerar....More then that, I couldn't garden organically, in my climate, without it. This product is a good guy....Hope that helps.

There is Bacillus thuringiensis - Kurstaki used to control many leaf chewing insects, Bacillus thuringiensis - San Diego used to control the larva of the Colorado Potato beetle, Bacillus thuringiensis - Israelensis used to control mosquitoes, black fly, and fungus gnat larva. There are some other strains of the Bacillus thurigiensis out there but these are the most common in use today. Since these all need to be ingested by the target pest where the bacteria spores then come to life, if the gut is the right one, and then digests the target insect from the inside out all of them are acceptable for use in an organic garden. They are fairly insect specific, and will not harm beneficial insects.

Thanks for all the replys.

Obviously the BT-Israelensis must be pretty tame on other creatures since I just discovered a couple little frogs living in my hydroponic tank which happens to have a mosquito dunk in it. I keep saving them and yet they keep retuning so I guess the hydroponic nutrient and mosquito dunks aren't bothering them too much.

Peggy g,
I definitely feel with you on the climate issue. I'm not too far away from you, I occasionally get called to drive over and work at the King Center on shows. I'm just up the NW corner of Orange County and it is so hard to get out and baby the warm weather crops right now as it is soooo hot.

Thanks again.

Here's how our provincial certifying body, Nova Scotia Organic Growers Association, classifies Bt in their materials list. I'd expect other certifying bodies to say the same thing or similar:
Bacillus thuringiensis (B.t.)
Allowed
Wettable powders and bait forms preferred. Liquid forms containing xylene or petroleum distillates are prohibited. Note that products (eg. seed potatoes, corn, etc.) that are genetically engineered to contain B.t. are not allowed (see genetically modified organisms)

tclynx, Always nice to hear from someone who shares the same climate. I've been absent from the forums as I've become a beach bum: learning to windsurf this last year; now that we're into the fall planting, I'm back! I'll keep an eye out for your posts. Fl. is a great place to garden, but so different from the rest of the USA....and a challenge to create that happy, healthy, soil. I'm trying to hit the garden early and be out by 10 a.m....to avoid the melt!

I was wondering if you had a brand name for us?

Depends on what strain of Bt you are interested in. Dipel is a common brand for Bt kurstaki or for control of caterpillars. Summit or Aquabac are brand names for Bt israeliensis or mosquito/black fly larval control.

All are available online but can also be found at most full service nurseries or garden centers.