Hi, Nautilus, the white fur is mildew and it will harm your plants ' but there is a simple cure, at your garden center you can bie a puff pack of sulphur most people use the green but the yellow dose the same job, just puff it on to the mildew, when Bamboo advised me to use this, my garden center said that the green had been taken off the shelves ,but in another center they had the yellow alonge with two diferent makes of green, sorry Bamboo, sorry about that I just had to straten up with Bamboo.and welcom to GOY.

Im finding it quite difficult to obtain ANY sulphur from any garden centres...I have the same problem as Nautilus on some of my indoor plants...:<(

This might not actually be a mildew infection - it's more likely its miccorhizal (I know that's misspelt, but can't remember how to spell it properly) fungi, which is often beneficial. If the plants aren't suffering, are healthy and growing well, don't worry about it. If the plants had mildew, you'd see it on the plants.

If the white fur type fungus is on top of the soil, then I would also say it is a type of mildew, probably caused by the compost being to damp or wet.
The beneficial mycelium from mycorrhizal fungi would normally be present within the compost and generally attached to the roots of the plant.

I would say better safe than sorry, Bamboo,even if it is not mildew the sulphur will do no harm, Motinot if you ask in the garden center, if they have not got it they will get it ,you are too valuble to loose as a customer, if I canot finde what I want I ask ,it works,

You can get results with malt vinegar or methylated spirits dabbed on with an artists brush. Sulphur indoors is bad for asthmatics or people with bronchitis.

I would be tempted to reduce the watering and see if that helps the problem.