The Rusty Patched bees are dying because of the over use of pesticides, climate change, habitat loss, and deadly pathogen found in most bees.
Farmers use pesticides with neonics in them that are deadly to bees. Also, things like gasoline and other greenhouse gases are affecting our ozone which are threatening the lives of bees. Another reason is habitat loss which humans are to blame for this one. Building roads, houses, and buildings affect the bees lives by tearing down nature and their homes.