Let's start at the beginning.
What are you using as a seed starting mix? Commercial product or homemade?
If the latter, please include the "recipe" and the treatment prior to seeding.

When I used to raise seedlings, a thin mulch of Pearlite worked for me. Good air circulation, of course.
Mike

did you sterilize the media ????

but.. once you introduce compost tea, for example .. your media is no longer sterile ...

explain what you mean.. when you say sterilized ...

pots.. media... water that you water with... tools .... watering can ... spray bottles.... etc ... everything?????

is this in the house... or greenhouse??

ken

There is no systemic fungicide that will help with damping off because that attacks the plants before they could uptake any.
Damping off occurs mostly because the soil the seedlings are trying to grow in is too wet and too cold, and may lack enough air circulation. Then again the pathogen that causes damping off may be in the growing medium or on the pots, trays, or what ever is used to start these in.

There are a great number of (mostly narrow range) fungicides which are used for treating seed before sowing, treating seedlings before re-planting and/or treating the soil. The correct one to use would depend on the particular fungi that seem to be doing the damage and on availability and allowed use of fungicidal drastic ingredients where you live and the suitability for edible crops in general or the specific crop in particular. For example, seeds and seedlings are often attacked by strains of Pythium sp. It is possible but not certain that that's what is infecting your seedlings. A commonly used fungicide to avoid Pythium and specific types of downy mildew attacks would contain the fungicidal drastic ingredients propamocarb (mainly fights Pythium) and fosetyl (mainly against downy mildew type fungi). Branding would be different depending on the market and jurisdiction. In Europe one such fungicide is marketed by Bayer as Previcur Energy and is labelled for quite a few vegetable crops. I suggest you consult you local extension or another specialist agronomist.
Nik

This post was edited by nikthegreek on Mon, Mar 17, 14 at 7:29

I'm thinking Agri-fos. Not the copper one but the systemic one.

Over the many years I've been gardening, I've tried a lot of things. Sterilizing everything that comes in contact with the seeds, besides the air. I don't have an air tight environment. All it takes is the introduction of some spores to infect and way everything to waste.

Covering the seeds with a fine layer of milled sphagnum didn't work, neither did perlite or vermiculite. Neither did speciality seed starting mixes or making my own.

I do it all outside now and don't have a problem with damping off. Since I'm growing ornamentals for myself and not veggies, there is no reason to get a jump on the season. In my old age, I'm trying to keep it simple.
Mike

So, please tell us -- what are you using as the media?

May i present that it might not be a media born fungus or damping off at all. If you are using water from outside rain barrel for example, can harbor harmful bacteria. I had the exact problem you did for about a month back in January starting flowers for spring i kept getting them to sprout grow well tell they were just about to put out true leaves then turn black on leaves then work it way down killing the plant. Nothing can stop it once its infected even systemic fungicide because its a bacterial infection. if you get water from a well and its not treated properly it could be it too. Maybe not effecting a person if they are drinking the water but seedling can be extremely susceptible to these things. I would try using 3% hydrogen peroxide about 1/3 cup per gallon does the trick for me. Now if its not this i have no idea what it could be.

Here is a link that might be useful: TheItalian Garden

...or, we could find out what media is being used, and go from there.

tj

This post was edited by tsugajunkie on Tue, Mar 18, 14 at 19:40