I read some time ago that citrus growers in California USA have to buy bees to pollinate their orange trees. Beeheepers can't just bring beehives into the area and the bees collect nectar and make honey in return. Because the orchards have been sprayed with insectides and herbicides. To the bees, this is the end of their lives.

Monoculture means only flowers for bees and other insects to feed on for a short period in a year. Weeding removes food for the rest of the year. So bees are dying off.

Monoculture can make economic sense but never ecologic sense. We will have to learn to eat money ;-)