Hey Cos, There's been much discussion about mealies on the forum - I thought someone would have answered your post by now. Go to search and search in this forum for imidacloprid. It works well - it will scar the leaves of Echeveria.

Imidacloprid is a systemic and can be applied through the roots, which greatly limits the chances of leaf damage.

I haven't tried malathion on jade, but have not had any bad effects on other plants. Malathion is mentioned on various forums as a problem for many Crassulas. As with any chemical, always spray with the plant in the shade, and not when it is stressed by drought or heat if at all possible.

Malathion is a relatively poor cure for mealies, which are protected at certain stages of their life by that cotton. Malathion also doesn't kill eggs so you are likely to need repeat treatments to get full control.

I have never had any difficulty with a 50/50 mix of rubbing alcohol and water in combating mealies. Wait and see what Norma says.