Chemicals, like neonicatinoids and many others, have killed bees and other insects. There are ways to manage pests that are not chemical dependent.
Flowers and pollinators are both critical to each other. Planet flowers, help pollinators.
Farmers can plant wildflowers in their fields, plant hedgerows, and sustain diversity to bring back the pollinators.
A master list for saving the pollinators!
The Xerces Society does terrific work, check them out.