Your description doesn't sound like a rust problem, which is caused by fungi that are usually airborne. Rust can begin by forming small orange colored spots on the foliage, which increases in size as the fungus multiplies. It is usually not fatal to the host plant, but can disfigure it. The spores overwinter in the soil and infect plants the following year.
Your plant may be reacting to cultural shock, if it's former location was total shade and it now receives part sun/part shade. It also must transition from potted plant with confined roots, to a landscape plant without bounds. Similar conditions to overpotting, which it resents.
Has a trunk formed yet?
Keep the roots evenly moist, avoid wetting the foliage and you might try shading it from the sun if it is exposed during the hottest part of the day. In time, it should recover on it's own.
Good luck!

Hi!

This is to tell the folks who have responded to my question on the problem my fern was having: Thank you!

My fern seems to be doing better now.

Two days after I had posted my question on the fern forum, I dug my fern up. I didn't think I had a lack of H2O on my hands, because I would water it every other day for five minutes each time. The problem was that I was actually giving it too much water.

When I had dug it up, I couldn't believe how easily it came up. My soil is mostly clay with some small amount of sand. I was truly expecting to feel like I was pounding against a wall with my shovel, but, no. The shovel went into the soil like slicing butter. That was the quickest I had ever dug anything up in my yard.

Anyhow, I re-potted the fern. I had clipped off the affected fronds, and just left it alone for close to a week.

I had examined it today. I am happy to report that there are five (5!) new fronds that are growing from the middle of it's trunk.

Thank you to all who had responded to my previous post.

Sincerely,
mbluetyphoon