Hmmm ... that looks like a calendula/pot marigold to me. And yes, that's mildew on the leaves. Has it been really hot where you are? They supposedly are more of a cool season plant - that might account for the wilty leaves.

I'd cut off the affected leaves, cut the whole plant back pretty severely, and see if it revives. Make sure the soil is well-draining and keep it moist, but don't overwater. Good air circulation should keep the mildew away. It could start putting out new leaves and give you flowers in another month or so, if all goes well.

Good luck.

PV

Hi PV, thank you very much for your reply. Yes, I did a search for Calendula and that's exactly what it looks like (or should look like) I'm not sure about how far to cut it back? or how to cut it. Can you please help me with this part? Thank you bunches!
Cadence

Cut it back by at least half of the plant - leave a couple of leaf nodes. Be sure to remove all the powdery leaves - and burn them, if possible, or toss them in the trash away from your plants. Give the plant a nice feed and keep it moist (not wet); try to place it where it can get good light, but not in the hot sun.

Funny how I came across your post last night - I sowed some calendula seeds yesterday and am hoping for blooms by September/October. If your plant revives, you should see new blooms by then too.

PV

Thanks again PV. I'll give it a go and see what happens. I really appreciate your help. I have several Begonias and I understand they are susceptible to mildew too. I will have to be very careful that it doesn't spread to them. Thanks again.
~Cadence~