Well, consider that plants as a group already produce endogenous insecticides by the boatload. Adding a strain that produces another one is just adding one more example to a pile that is already huge.

Which is not to say that there aren't any risks at all. But plants and insects are already locked in a millions of years long battle/cooperation. And look how quickly insects have developed resistances to our modern pesticides. Adaption to something new appears to take years to decades, not centuries or longer.