Hibiscus: Hibiscus laevis, 0 by Chillybean

Chillybean wrote:
I discovered a nasty on this plant. It seems the corn is not enough for them, so the Northern Corn Rootworm adults (which are a small beetle) go after any variety of sunflower and also hibiscus to eat all the pollen. I am not sure what other parts as they get deep into sunflowers and the seeds never form. I find the rootworms in the closed up Rose Mallow blossoms, doing or eating who knows what.

When this Rose Mallow first bloomed, we had bumbles pollinating, but now they cannot get to the flowers early enough. I squish and knock the rootworms into soapy water. Are there any other non-chemical controls for these bugs?? I have used pheromone traps for other bugs in the past, but they also caught beneficials, so I do not use those any more.

I hope someone reads this. I've noticed this forum doesn't seem very active.
Thank you for any help. I've included a picture, so you know what they look like. They start out almost tan, but turn brighter green as they age. They are about 1/4 inch long.