It is impossible to starve thrips to death - it is one of persistent old wives tales. They just move to the young leaves and scar them badly.

I am thinking that if you disbud everything now - and spray 3 times week apart- you will get first good buds opening for Christmas.

If you have AVID - it will work, Merit is good too. I did buy Bayer "tree and shrub" with imidacloprid, but didn't try it. What stopped me - there is an another ingredient besides imidacloprid in it - and I was not sure how it will affect the plants.

Thrips are persistent... and can come from outside with a bunch of flowers too...

I.

Thrips can sneak in anytime and they may not have come in on your new Millenia. I have used Schultz Houseplant Insect Spray with good results. The main ingredient is Pyrethrin from the Chrysanthemum flower. This may also be the basis for dog & cat flea spray which older magazines often site as being helpful.
You might consider using the RID treatment: 2TB of Rid Lice Shampoo, 1 or 2 tsp Murphy Oil Soap dissolved in 32 oz spray bottle of warm water. The plant & soil should be drenched, allowed to sit about 20 minutes and then rinsed. One grower said it was 100% effective with a one time use. Thankfully, I haven't had to test this last method, but I think it would be my choice if I encounter thrips again as it is purported to do no damage to the plants.
Hopefully, you will be able to get these critters under control!

The main thing - is to disbud and treat it repeatedly - soaking every nook and cranny. Anything will choke the thrips on the plant - but there are eggs and immature insects hiding in a soil. Seems like the last method can damage the plant - it will look like a leopard after this kind of treatment - I agree with Terrilou.

Irina

Happens to everyone. Best of luck!