If you look closely, you can see 4 corn rootworm adults on my first Rose Mallow bloom of the season. Row corn is planted closer to us this year, so those beasts got here sooner than last year.
A couple evenings ago, I went out to shake the beetles into a bucket of water. And found some already had gone into the unopened flowers. I got them out and early the next morning, they were hardly on the Rose Mallow, but a couple of hours later!!! Last year was the first year they bloomed for me and I was so thrilled.
Articles say the rootworm beetles prefer yellow composites, but oh! not these. We've got yellow composites all over the place between the native sunflowers, Black-eyed Susans, Ox Eyes, etc. They are on some of these flowers, but their greater numbers seem to be onthe more tender plants, like this hibiscus and the Tick Trefoils I just got this spring.
I'd like some of the Rose Mallow to go to seed, so I just may need to hand pollinate. I've never done this before, but I am sure there is an article somewhere about it.

And I will give your idea a try! I just need to find some of these. Wal Mart has a large craft area, so will check there first. I want to collect some Spiderwort seeds and think this might help catch them.
Thank you for linking to your idea. I could not remember where I saw it earlier... here or somewhere else.