The rusty patch bumble bee in Eastern America are endangered. Their population is showing a continued decline. Many factors contribute to a species decline including several interacting stressors, pathogens, pesticides, habitat loss, and small population biology. Insufficient floral resources reduce the individual’s response to pathogens, pesticides, and insecticides. U.S. Fish and Wildlife developed an active plan to support and encourage this species survival.
https://www.fws.gov/species/rusty-patched-bumble-bee-bombus-affinis