Mick, I have seen something similar to what you have described, but my eggs where clear and very small and appeared to be on a fine web also, almost made me think of thin strands of a fiber material, like strands of a carpet almost? I thought at first it was sap droplets, but then I realized it was only in the medium, and the only medium I have found it in is my PrimeAgra. I figured it wasn't a fungus so I treated with insecticidal soap last week, I haven't checked to see if it came back yet. If I were you I wouldn't take any chances! I hope mine doesn't develop into what you have....yuck!