Do diesel engines need spark plugs to ignite the fuel?

Diesel engines use heat and compression to ignite fuel. Although not needed in more modern diesel's many had glow plugs in a similar placement that is used to add the required heat for starting, but are not needed once at temperature. With higher injection pressures allowing a finer mist of fuel, thus requiring less heat and compression, glow plugs have largely been eliminated (but still have other heaters for cold weather starts.)