not noticed mildew before on pansies. improve the watering and you could always try a fungicide spray. if only a few leaves affected pull them off and pop in household bin.

I have Seaburn, and blackspot, so fungicide as you say.

We changed to violas the last couple of years, ours looked so good I have one pot from last autumn that flowered beautifully, I cut them
back a few weeks ago, gave them a feed and they are lovely again.
I,ll have new ones this autumn though.

2 winters ago my pansies had mildew and the violas were covered in block spot. last winter I just tried violas and they did not show any signs of either. I found cutting it all out worked but you have to wait longer for them to reflower.

Now I grow alpine violas and they grow die back grow again every year.

And they are so pretty I go for the orange and yellow mix...citrus I think, even on the darkest days they look cheerful

I haven't tried alpine ones, I,ll look out for them