Mealybug HELP!

[Pilif]

a) get poison that works against mealies, preferably a systemic insecticide (i.e.: an insecticide that has to be taken up by the plants (via the roots). Mealies suck out the plants juices so they'll also eat the poison that way.).
b) poison plants as instructed by your insecticide.

[majcka]

You can allways use this:

A hommade thing with water, soap and cigarette. It goes like that:

1 liter of water
1 cigarete tobaco
drop of liquide soap.

Mix all of that and live for a week. Then you can water your cacti with it or if you filtrate it you can spray them.

No other poison needed. And it's growing season, so you can do it avery week or two.