What would happen to owls if the grass was sprayed with an insecticide?

Keep in mind the owls eat the mice that eat the insects that eat the grass

The owl would barely have any food source cause the mice eat the insects which eats the grass and the grass kills the insects therefore the mice wouldn't have any food so the mice dies then the owls will have no food well i mean they would but if you take one animal off the food web it can mess up the entire food web

If the grass was sprayed with insecticide it would start to kill the insects which means that the mice now have less food and would start to die causing the owls to have less food since the mice would starting dying also since their food source is depleting.