Could be mealy bugs. Wipe away the 'white stuff' with a q-tip and alchol, it won't hurt the plant. And spray with a general insecticide. The link has some images and more info. Here is a link that might be useful: http://www.denverplants.com/foliage/html/Mealy.htm

Gidday Ed, Looks like some of the bugs are scale. Either way, it looks like natureal or hand methods might not be enough. I'd water the plant with a mix of Rogor. This systemic should do the trick. Also another good thing I do, is when I repot my plants, I include some of David Gray & Co "Systemic Insecticide Granules". This systemic insecticide is granulated and is good in the mix and gives a few months protection.

Your cactus are super etiolated. The new growth is reachin for that sun;)! If this were mine I’d cut the etiolated pieces off with a clean sharp knife, and begin to acclimate the cactus to stronger sun. Not sure if you know this, but those little white fuzzies are called glochids. Protect yourself from the, because they will get stuck in your skin, clothes, and everywhere else. Glochids are VERY irritating.

Duplicate thread - please go to= THIS THREAD (CLICK ME PLS!) =