When to spray scale, mealybugs etc on indoor plants

Hi Pip,
Use methylated spirits, dab on with a fine artists brush at any time of year.

the meths is about the only thing that will work on the scale. If you can't be bothered to treat the mealy bug in this way, you can buy sprays which treat the condition, and these can be used whenever there's an infestation.

Thanks Doctorbob and Bamboo