A while back someone asked about controlling flying insects without using insecticides. I use "White Fly and Aphid Trap", manufactured by Biocare and/or "Sticky Stakes" and "Sticky Whitefly Trap" manufactured by Safer. All of them are yellow cards coated with a super-sticky surface. The Sticky Stakes are used adjacent to specific plants and the traps are used to control flying insects in a general area. All of these are non-toxic. The insects are drawn to the "yellow" and once they touch the card's surface, they are toast. Below are several pictures showing two cards that have been in my "Orchid" greenhouse for three months, and a new card, just hung a couple of hours before the photo. You can only see perhaps 50% of the (stuck-on) insects because of their tiny size. The cards are two sided, so both sides look the same. There are probably 100 insects on each side of these two cards.

You can also buy just the sticky stuff and make your own from yellow card stock. (I just happen to have a bunch of bright yellow file folders left over from a previous job) Custom sizes and shapes made easy.
https://www.amazon.com/dp/B0039CKKCE/

Good information. In the future I'll just make my own. Thanks.

Additionally, I'm trying out a new product this year for controlling wasps. Every year, the darn wasps take over my greenhouse and drive me out weeks before my plants are ready to set out. This year, I'm trying this wasp-specific sticky trap, and so far the results are encouraging. I hung one at the east end of my greenhouse as soon as the weather started warming and we started seeing wasp activity. Caught a BUNCH of them on this thing. But it got full, and we got a lot of wind and rain and I started seeing wasps buzzing around inside my GH again. So we hung up a fresh one, and I opened up the GH door to let the little rascals get out. It appears that they go out, fly around for a while, then try to get back in by the window on that east end. Just yesterday I was working in the GH (which after a couple of days of doing this, is amazingly wasp free!) and saw one hovering around that window. Sure enough, it landed on the trap and was promptly stuck! Made me smile.
Apparently, there is something attractive to wasps about the pattern they print on the cardboard with the sticky stuff. This is the first time I've ever had any luck trapping wasps.
Here's a link to the manufacturer's information page:
http://www.rescue.com/product/...

Interesting and it actually works!

So far, so good! And I think I'm mostly trapping the female wasps, so maybe we won't have such a bumper crop of them this year! It's probably a bit early to get too enthusiastic, but at least for the moment, it has made the GH useable! Heh, took out a big fat one in my kitchen window just a minute ago, too. I LOVE rubbing alcohol! Hey, maybe they call it "rubbing" alcohol because it "rubs out" nasty bugs?

We have our share of wasps, but thank goodness, nothing like what you are dealing with.

>> I think I'm mostly trapping the female wasps,

Maybe the "Visi-Lure" (R) appears to wasp-eyes like a big, attractive male wasp?

If you want to trap biting flies - use the sticky stuff (Tangle Foot - Tangle Trap Sticky Coating) painted on a blue color .
Learned this from a plant friend. She attached a blue ball (to my eye the ball appeared to be a royal blue color; don't know what color the flies saw it as.) to a hat, painted the blue ball with the sticky stuff, and wore the hat on her head. That put the ball roughly at 6 feet from the ground - according to her research, the ideal height to attract the biting flies such as deer flies.

That's interesting! I wonder what color will attract cluster flies? Tried yellow, but that didn't work too well. Although, come to think of it, they seem to land on anything warm, which is generally something dark.

This is just an inventive guess on my part. Take a light source (flash light or electric light) cover it with an opaque white covering (similar to that seen on some ceiling light fixtures?), apply a layer of the stick-um and wait for the cluster flies. They are attracted to light and to light colors, so this should work.
[and yes, I just made this all up right this minute; if anyone patents the idea, please send me a check.]