What does the root look like? If it is soft and water comes out when you squeeze it,i would say it might be phythophthora root rot. If it is,the tops will look discolored-maybe yellow,red,or brown and may even look like boiling water was poured on it.I have had this disease in my patch and i use subdue gr and aliette wdg fungicides. Without seeing your plants or having a good description,I really dont know what is causing your problems.You can find some information about ginseng diseases online.I hope I have helped some,but like i said a better description of the diseased tops and roots would help.GOOD LUCK
