Bacillus thuringiensis kurstaki is most recommended for the control of caterpillars.

We grow passion vine FOR the caterpillars. I don't know what kind of butterflies you might have in Brazil, gulf fritilary caterpillars are what eats this vine here. (Not that the caterpillars are pretty, but the butterflies they turn into definitely are.)

I expect that ifraser is growing passion fruit as a crop, so he needs to keep the caterpillars down to a population that won't decimate all of his plants!

I'd like to see pictures of the caterpillars, too....out of curiosity. Do you know what kind they are, ifraser?

Yes, they are Gulf fritillaries. They are not restricted to the Gulf of Mexico area apparently.

Interesting! I guess if you want/need the fruits, it might not matter how much you appreciate the butterflies. Sorry for the dilemma!