White powder residue ????

i have a white powdery residue on the leaves for about six months i thought i got rid of it with a product i used(cant remember what the name was) but it was a milky color and organic...I was to apply it by spraying and it went away when i switch rooms but came back...HOW DO I GET RID OF THIS STUFF!!!! please help!!!!

Mighty Wash and Neem Oil.....

and just apply that and it goes away?