Do you have to use sweet scent to catch suicuneraikouor Entei?

you don't HAVE to but it can help. youre main concern is getting the creatures in the right area this involves going back and forth between an area and looking at youre pokedex then provided youre seen one before you have to get it so that you and it are on the same route then you could use sweet scent to try to pull it out but i perfer to use repel and walk up and down in the grass until it shows up this will work where the Pokemon that live there naturaly are weak entei/and the others wont be afected cos there at leval 40 so that will be the only creature to attack doing this is allso a good way of getting them to show up the first time aswell ohh and a Word of warning take Pokemon that know mean look so you can trap it in cos they like to flee alot and take alot of the time balls hope the hunting goes well!

urm apricon springs to mind but im not sure