Sudan red 7B, also known as fat red, is a non-fluorescent stain. It is effectively used to stain lipids and is used to indicate the presence of suberin in cell walls.
[1][2][3] Sudan red 7B acts as a marker for formosan subterranean termite, 
Coptotermes fornosanus Shiraki.
[4][5]Appl- Sudan Red 7B has been used to stain root sections of pearl millet.
[6]