Thankfully, Japanese beetles aren't a problem in California. In fact, I don't think they are anywhere near California. Whew!
I built a similar looking trap, though much smaller, for attracting and killing fruit flies that have been a problem near my worm bin. The bait is vinegar. They fly through the funnel and then can't fly out.
That cardboard box salmon looks delicious! Reminds me of the solar cooker I made once. I like that you use multiple web resources, e-mails, and your own assumptions before seeing what happens... on camera. This approach makes for very suspenseful (and occasionally hysterical) viewing. Watching Gardenfork is much more fun than watching scripted gardening and cooking shows where everything's pre-pla...
I built a similar looking trap, though much smaller, for attracting and killing fruit flies that have been a problem near my worm bin. The bait is vinegar. They fly through the funnel and then can't fly out.
Did you grow hot peppers and tomato...