Here's a perspective from someone with a smaller collection than y'all have
been talking about. I have about 200 plants, including a fair number of
young adults (have been growing only 3+ years, and made all the usual newbie
mistakes in the beginning).

My Phals decided to attract mealies last spring. Also had a run on thrips
in the Vandas and Catts shortly after that. When the mealies hit, I used an
alcohol/soap/water spray and soaked the medium as well. Then a couple of
days later I pulled them from the pots and found the rats on the roots,
coming back. I sprayed the bare rooted plants with the same stuff, and
repotted. End of mealies, gone, over, done.

When the thrips descended I treated the entire collection with Orthene,
leaves, medium, benches, everything, and repeated ten days later. Haven't
had a probelm since then, but when (not if!) an infestation occurs again,
I'll do the same thing. I grow outside, so the little geckos do help out,
but when you get hit with something heavy even the little guys can't keep
up.

BTW, careful using label directions with Orthene liquid. Two
teaspoons/gallon will do the trick. The label calls for three tablespoons.
Too much stress for the plants!

Diana