Ah Kansas! Yellow Everywhere.

The sunflowers and other late summer flowers are in full bloom. Yellows dominate the landscape. But one thing is somewhat missing--the pollinators. I hear and see some bees and flies, but not in proportion to the supply of flowers. I'm not sure whether the continual use of pesticides has severely reduced the numbers of pollinators, or if there is another reason for the depopulation of insects. Grasshoppers and kin are doing well. I know plants have received more rainfall than normal, thus they are prolific. But what happened to the bees and pollinating flies?