Thanks Wilkie.
Interesting you should ask just now. I just posted about the new ECF Fungicide Report.
Most all fo the fungicides are expensive...some more than others. The copper products are likely the cheapest to use, but also highly subseptable to resistance. Most of the manufacturers (and there are a TON of them out there right now that are labeled for ginseng --I've researched 45 for the report), recommend a tank mix to help decrease the possibility of resistance. Captan isn't labeled for ginseng at all as far as I can tell, but Rovral 4 is, and is often recommended by the copper fungicide manufacturers as a tank mix (so long as it is consistent with the Rovral label).
The big key is to change up the FRAC groups. If you are using a M1 (copper products mostly) then you want to change to something different after that. I'm going to tell you to spray a preemergent drench of copper and then go back after emergence is about finished with Ridomil Gold SL or GR which are FRAC group 4. You might also use Aliette which is FRAC 2. Both Ridomil and Aliette are systemic and help with soil borne diseases such as Pythium and Phytophthora which cause root rot. After that, you can adopt a wait and see attitude and apply a protectant and others as necessary for the conditions your plants are in.
That is actually the reason I put this report together over the past few weeks. I get asked about this stuff, and it takes a lot of time to research it and get familiar enough to know what fungicides work for what diseases and what their compatabilities are.
