About 4 days ago I found a large amount of caterpillars (Pieris brassicae) in my radishes, I took them aside for seeing how they grow and I am out of radishes to give them. I bought a cabbage in the supermarket to give them as food but I am concerned it could be GMO anti pests which to my understanding could kill the caterpillars. I took one of them aside and it is happily eating the cabbage, if this cabbage is designed to resist pests how long would it take for the caterpillar to die since she started eating?
Thank you so much for the info :)