Bt and the Aroian lab in a nutshell  

The Aroian lab at UCSD uses C. elegans to study Bt (bacillus thuringiensis). Bt is related to a species of bacteria that causes food poisoning and also to the bacterium that causes anthrax (bacillus anthracis). Bt kills only very specific species of insects.

Many organic farmers have used Bt for over 50 years as a pesticide to control insects. Bt is also used to control mosquitoes, and other insects that bite and spread disease. And now, genes from Bt is used to modify plants so that the plants produce the Bt toxins and kill insects that try to eat them without any external spraying.

So with 50 yrs of use, you'd think we've got everything figured out about Bt. But the truth is, we don't know much. Most importantly, we don't know how it works. Some would argue, why bother knowing how it works if it's been working for the past 50 yrs. True, but then there is the problem of resistance. What if insects turn resistant to Bt like many bacterium have turned resistant to antibiotics?

For every single synthetic pesticide that is in use today, there are species of insects that are resistant to it. Many of the more powerful synthetic pesticides have been or will be taken off the market due to health and environmental hazards. There have been reports of 2 species in the field that are resistant to Bt, there will be more. So in the hopes of preventing this, labs like the Aroian lab are trying to figure out how Bt works on a molecular level and maybe someday find out a way to prevent resistance in insects.