I'm not sure about the fungus problem, but when I rooted my maid of orleans last year (geez that stuff takes forever to grow!), I didn't put a cover on the whole thing, I would just mist it occasionally. It may be that the humidity is too much for your plants maybe? You might want to try and cut down on that, and maybe it will keep the rot from spreading. Just a suggestion of course.

Merisiepoo, you may be right. I removed the dome temporarily for a day and I do not see any more spreading of the fungus growth. I know the reason now, since there are no drainage holes below it is causing over humidity inside. Generally i propagate in pots with holes which does not cause that issue.

Kandhi:
I have developed an elaborated mini-green house for germinating seeds and rooting. It takes a few years to learn how to control mold. Any unsanitized organic media in still air condition will promote mold to grow.

My media is a moist mixture of 50% perlite and 50% ground peat that is treated in microwave by heating thoroghly twice to kill fugus.

The seeds and cutting are treated with about 100 to 200 ppm bleach for 20 min. The seeds and the cutting is then rinse off with anti-fugus copper chemical solution( you can rinse it with bottle water if necessary).

Now you have clean media and clean cutting. Possibly the rooting shall have no moldy problem. But you have find a warm place. I keep my Tropical Fish Tank converted into mini-green house at 75 degrees F with grow light about.
see the photo.

Here is a link that might be useful:

The seedlings in Feb, 2005, ready for graft in late March.

The appearance of the leaves can be improved to deep green with proper amount of 'chemical fertilizer' solution with minor elements. They grew so fast and needed more fertilizer. I used less, afrid of burning the seedling.

Here is a link that might be useful:

Kandhi: Try a simple method. Use only clean sand for rooting with your covered container in early summer. You can check callus about in two months.

Then use proper fertiliser solution.

I have rooted several types of jasmine. I do not do anything fancy. I just use regular potting soil and halved 2 liter bottles. The only thing I do to stop fungus is to spray with diluted hydrogen proxide. Since I only do it for my pleasure and to share with friends I can not justify spending alot of money on setups. I know that my way is not for the serious gardener but it's fun for me.

longriver - thanks for the tips. It is from you and other garden experts I have a learned a lot on tending the fragrant plants. I propagate to experiment and fun and give them the tiny plants to my friends after rooting. when I see the roots, it is a sense of accomplishment and I enjoy doing it. It feels good to share plants.