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Use of Bacillus thuringienis israelensis for Diptherid control in vivaria?

SludgeMunkey

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As I prepare to be crucified for bringing this up...;)


I regularly utilize the off the shelf products formulated from dormant Bacillus thuringienis israelensis in my outdoor water features as a control method for mosquitoes, assorted gnats, black flies and the like.

After remembering reading posts around the web about "gnats" and the like infesting enclosures, I did a bit of research on this bacteria. Apparently, there is little data I could find on their effects on amphibians other than it is "harmless".

This got me to wondering if a version of this control method for diptherans would be viable in enclosures.

(Then again, the way my mind works, I started looking for data discussing if exposure to this strain affects their immune systems in such a way making amphibians more susceptible to iridioviruses or any of the strains of the dreaded fungus...Methinks I see another research paper to start working on...)

Anyway, as I am just an undergrad full of crazy ideas, I was wondering if anyone on here had thoughts on the topic.
 

fabri

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The proteins of the B. thuringiensis are prototoxins and are higly specific ( they need specific receptors to work) and they have to be ingested to be activated.
To develop theyr toxic activity they need a pH > 9 (thats why it's not adviced to dissolve the product in water with a pH higher then 8). At this pH there are enzymes that degradate part of the B. crystall (they are sold as crystalls and to release the toxins the crystal have to be degradated) and the small pieces that are not degradated penetrate in the peritrophic membrane of the middle intestine interacting then with the epithelial cells. Once reached the epithelial cells they bound with specific receptors and the cells lose their functionality causing the paralysis of the intestinal muscles (the insect is still alive but it is unable to feed himself). Once that the stomac tissues are destroied the condition for the sporulation are created. The B. moves to the insect blood and it's over.

The stomac of the amphibians, mammals birds and etc have an acid pH in the stomac and the B. toxins cannot be activated thats why is considered safe.

I'm sorry for my english, if I was not clear just let me know and I'll try another time to explain it
 

nwmnnaturalist

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It really depends on the enclosure type and the amount of water/breeding stratum that the critters are coming from. Bt has been marketed as one of those 'perfect pest control' products, and you may have to dig for some 'dirt' on the material. Normally it is a fairly safe product to use, but when used irresponsibly it can do more harm. I'm not sure what kind of impact it would have on captive animals, so I couldn't help you there. Bt is present naturally around us, but nowhere near the concentrations that the products hold.

As for control of flying insects in captivity, I like to use a material called Tanglefoot, but it's tricky to use. It is some of the HARDEST stuff to remove. I smear it thinly on a piece of cardboard or the like, then create a cage around it with hardware cloth (with 1/4" - 1/8" openings) to keep the beasties from getting stuck. It's a death sentence for anything stuck to it, since you can only remove it with mineral spirits or the like. But in a safety cage, it should be okay and the flies should be able to enter and get stuck. I like to use bright yellow tagboard or card stock/construction paper since it attracts them more.
 

Ed

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The problem with the glue traps is that they only work for the gnats that have left the enclosures. This doesn't help a lot if there are any that are still breeding within the enclosure. The nematodes are harmless and will control them for a long time. They will control some of the other flies such as moth flies that also sometimes establish in the tanks.

Ed
 

Justyn

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I've used it for years and it works great! Give it a go.
 

fabri

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Nice to know it and thanks for sharing this information
 
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