white spots on lampranthus leaves? advice please

[nick bayne]

I recently noticed white spots occurring on the leaves of a lampranthus (or drosanthemum). I originally plucked off the offending leaves but the problem has reoccurred en masse. Any advice as to what it is and how best to deal with it. I have used Provado insecticide but this has had no effect.

[Saxicola]

Can you give us some pictures? There are lots of causes of white spots ranging from mealybug and whitefly to fungus to simple hard water stains.