Scale Insect...

Steve the Gardening Vet

I have an orchid that (with no new plants having come into the house) has mealybugs. I've owned it for years so no idea where they came from. I've sprayed it once with imidacloprid and they have reappeared a couple of months later.

Do I ditch it? Take it all out of the pot and spray the roots too?

How long would the little swines take to drown if I soaked the root ball for a day..?

Hostafan1

dab them with a cotton bud dipped in meths

Steve the Gardening Vet

I corrected it, mealybugs.

Steve the Gardening Vet

I wonder if the issue is that it is obviously in bark and not soil so they can track down along the green roots.

Hostafan1

you can tip them out of the bark easily, deal with the bugs and stick them back into the pot/ bark. 

Steve the Gardening Vet

That was the option I suspected was best. Problem is that they are stuck deep into the root bases so systemic chemistry seemed best.

Borderline

If you are sure it’s Mealybugs, remove the bark off and replace, and clean up all the stems as others have recommended. If you have had this plant for a while with no issue until recently, it is possible it’s spread from another plant. Even if you have dealt with this plant you may need to keep an eye on that plant and other plants over the next month or so. 

Steve the Gardening Vet

I have no idea where it could have spread from though!

Borderline

Without putting you off anything but fruits and vegetables bought from supermarkets, grown from your garden can infect your plants. Other areas could be fresh cut flowers or simply leaving windows and doors open for air.