From what I've found online about IGRs they mimic hormones that control parts of the insect's life cycle. They might, say, cause something to happen earlier or

From what I've found online about IGRs they mimic hormones that control parts of the insect's life cycle. They might, say, cause something to happen earlier or later than it naturally should have occurred. There are many things in an insect's life cycle that have to occur at the right time for the insect to reach adulthood and reproduce. Screwing up the timing doesn't kill the young insect, but if it makes it so it will never reproduce. Keep doing that to the insects in a place for a few generations and they die out. Most of us probably do not want to do this, but cockroaches are in fact edible by humans. If IGRs mimic cockroach hormones, then eating a small amount of cockroach IGRs should not be any worse than eating some cockroaches.