First summer outside.....
 

7 cattleyas, 1 dendrobium, 2 brassias, 1 vanda, and 1 paph....

They have enjoyed their 1st summer outside, new growths came in crazy fast, and bigger than all others on most. I live in Michigan and weather temps are getting close to bringing them back in. Should I treat for pests whether I see any or not? If so, what do you recommend? I'll be watching closely for frost, but am curious as to what temperature should I avoid, i.e. not below what number? Any other thoughts or suggestions? I really, really hope that the amount of sunlight received will lead to my 1st cattleya blooms. Thank you for any and all input

I think you would be smart to treat. My preference these days is Azamax, as it is effective on all stages of insect and mite maturity, unlike most pesticides that only work on adults, and is a pretty good deterrent, as well.

Treat at label strength three times at one week intervals.

Personally, I don't let any of my plants go below 45°F if they are bone dry; 55° if the potting medium is moist. Phalaenopsis come in before it even thinks about dipping into the mid-60's.

I do have azamax from a previous spider mite outbreak I had a couple of years ago. Use it in a sprayer and mist everything above the roots?

You can also use it as a soil drench. I'd also soak the pots in soapy water to drive out soil pests.

Ironically I've had more trouble with bugs indoors. Make sure that your indoor stands, saucers are clean. Most importantly, check hinges and shelving carefully. Last year there were mealybug egg cases ( white fluff ) hidden in the shelf hinges. I only discovered them because I decided to adjust some shelves. Explained why the previous year I had mealybug infestations as if by magic. I'll be spraying my outdoor plants at least 2x before the dreaded indoor move.
And check indoor tropical plants too, while you are still able to give them a thorough spray outdoors.

I don't know what part of MI you're in, but here at the base of the thumb (25M west of Port Huron) we've already had temps in the mid to upper 40's. I personally wouldn't press my luck on keeping them outside any longer. Can I assume that they've been out all summer?

Yes, all summer. Live in highland/milford area

It was 44f a couple nights ago. Mine are in but w/o 3 sprays. The problem for me are the hitch hikers in the pots. You may flush them out but this spring In found a slug that had somehow overwintered in a plant that had not summered outside no less.

You live in an area I used to spend a lot of time in when I was younger, Proud Lake and Highland Recreation Area. Both were excellent places to hike and enjoy nature.