Clear film coming off stem

From a fellow grower:

I have a few questions. The girls are doing fine. They are also most 30days old. I noticed yesterday that there is a clear film or skin coming off the stem. Is this Some thing to be worried about? I have also seen some small black gnats, I think they are Fungus Gnats. Nem oil? Or do you recommend some thing else. Can I mix azzmat and nem oil together? Thanks for the help,

You could use a Drop of dawn to a quart of water to kill those bugs