Were you intending to cook them? ;-) That's what you'd be doing.

There are products made for dusting seeds. Check at a good nursery.

Basil Downy Mildew is a new and devastating disease that has been spreading throughout the country rapidly. There are no known substances for "dusting seed" that will help. They may identify something eventually - but for now, the only method of making sure you are not passing the disease in seed is a commercial process to steam the seeds.

How this is done I have no idea, but I sort of doubt a home grower has the proper equipment, let alone training, to be able to do it. Sadly for the OP.

Here is a slideshow presentation that lists fungicides tested to control the disease in the field. The vast majority of them are NOT organic. But this is only for growing plants. Since basil downy mildew can be passed on via infected seed, this is a real concern for growers and seedsmen alike.

Here is an article describing how it spreads and reproduces (in layman's terms).

If you have had an infestation of basil downy mildew, Cornell University is tracking its spread. You can help by using that form to report an infestation of basil downy mildew. It would be most helpful if you could get confirmation of the disease from your local extension agency first.

From the Cornell report:

• "In a 2011 study, products with the most consistent control were MilStop and OxiDate, but even in this study the disease was not stopped; it was only reduced about 50 percent compared with the control. The challenge of controlling downy mildew is the need for blemish-free herbs when marketed as fresh sprigs when a 50 percent reduction in symptoms is not enough. Additionally, infection occurs on the underside of leaves, a difficult area to reach with a fungicide, especially for sweet basil, as leaves often cup downward. I donâÂÂt believe fungicides are the answer."

Here is an article about how to perform hot water seed treatment

However this is of questionable value in treating basil seeds according to Maine organic Farmers information page on downy mildew:

• "While effective, treating basil seed with hot water is problematic because the seed exudes a gel."

They do not explain WHY this is problematic - is it because the gel prevents the treatment from reaching spores that have gotten under the gel layer, or is it because the treatment removes that gel layer and reduces the viability of the seed?

In any case, the current recommendation is NOT to try to save seed if you have had infected plants - even from healthy plants. Because the spores are literally EVERYWHERE and seed from a healthy plant is just as likely to be just as infected as seed from an infected plant.

This article mentions that

• "Some seed companies are now steam-treating basil seeds."

They do not say WHICH seed companies, but I, for one, would certainly like to know.

They do suggest that the variety "Eleanora" seems to be partially resistant to the disease - but so are a lot of non-sweet basil varieties such as...

Thanks! I was aware of the Cornell report. I actually sent them one of my many infected plants this summer to help try and find a way to get rid of this disease. It is just sooo discouraging! I've never had a problem growing basil and now I am almost scared to grow it!

Yeah, I'm right there with you. I've been gardenless for going on 8 years now and I had big plans for the basil next year.

Now I'm almost afraid to even try.

I have a packet of Burpee basil I want to plant, but am a little nervous as I don't want to infect the eleonora I planted. Should I not worry and just plant them or is there an easy way to home treat?