Photo #1 Sunburn
#2 Normal coloration
#3 Normal coloration
#4 mechanical damage

I wouldn't worry about any but #1 if more of the brown streaks appear. Otherwise you're cool

Lainey

Thank you for looking, I hope that you are correct. I absolutely love the Krossa Regal and Striptease. It would be heartbreaking to lose them. On the Striptease, I am concerned about the white appearing in the middle edge of the margins.
Daniel

I share your concerns. Are your plants new this year? I have also been concerned about my hostas but only the hostas I have purchased this spring. All of my hostas from 2005-08 look great !!! I do not buy from the big box stores but only online nurseries that are AHS members. However, at least 12 of my new hostas planted within the last month have signs that look like the nematodes pictures. Tonight I cut off most of the defective leaves (making sure I left enough for the plant to absorb light) I will observe them further- I would hope the big online nurseries test their plants. Fingers crossed !!!!

Daniel, your Krossa Regal is sporting, the leaves with the streaky mottling indicate that possibly more may show up next year, perhaps even some that have gone to the next stage and start to show medio variegation, all quite exciting really. What I'm not excited about however is the interveinal brown patch in the first shot, that to me looks like early signs of foliar nematodes. Sunburn does not limit itself between veins like that.

The thin white stripe in your Striptease is to be expected, just take a look at the pictures of it in the Hosta Library.

The Pineapple Poll looks like some form of mechanical damage to me as well.

So what exactly is sporting and why is it good? Does it mean that my solid colored plant is developing streaks? Does this make a plant more or less desirable?
What is the definition of mechanical damage?

Daniel, sporting=mutating and in Hostaholic circles that is considered exciting as it may well lead to a new, yet unnamed variety if you're lucky. BTW, do the 2 leaves you show come from the same spot on the crown, are they part of the same shoot or are they on different sides of the crown?

Mechanical damage can be the result of various actions where the leaf ends up getting squeezed or crushed. The brown part of edge of the leaf in question reminds me of dessication, inadequate moisture take-up because of a small root system or plain lack of water, it's kinda hard to tell for lack of focus.