some sort of scale. white falkey bumps with brown dot centre

[SirLSD]

no pics YET. this scale type problem results in white/grey scale that is easily rubbed off with your finger. it has a little brown dot in the centre of the white scale. they flourish in shaded areas and result in large patches of brown scar tissue on the cacti. found in perth. what is the solution to this problem?

[XavierDass]

I've had success with neem oil, used once the sun is soft and setting, to avoid adverse affects from the increased photo-toxicity.

It works by suffocating scale and other pests such as aphids. I find it best used in a regimen as a prophylactic rather than a treatment (once original infestation is stamped out).

 

I have seen some people report adverse affects on their cacti from various horticultural oils, though applying around sunset has been working well for me.

[Evil Genius]

Get a brush and scrub them off carefully, then start treating it with a pesticide like Azamax, Spinosad, Imidacloprid, Pyrethrum,White Oil, Alcohol etc. All of these can cause adverse reactions or burns, so make sure to follow all instructions.