I call it WWD 'warm weather disease' and it affects my spring planted peas every single year, even in new soil.

My peas end up looking exactly like yours do where they begin yellowing at the soil line and working upwards.

In the past I have been able to keep them around a bit longer by spraying with neem oil (a mild fungicide/inseciticide), but it's really the heat that's the problem.

My peas just recently started yielding and that's only because our 80f+ temps dropped. Today the high will be ~60F+ and raining.

Anyway, there are a couple things you can do which may or may not help. If you have some miracle grow or other fast acting fertilizer, fertilize them to see if it will prod them into producing. In spring it's always a race for me to get peas to produce before the heat does them in so I usually do give them a couple nitrogen doses even though they technically aren't supposed to need it.

Please do plan on a late summer sowing for fall harvest though as many gardeners find fall plantings of peas work out much better than spring plantings.

In short, I don't think there is anything wrong with your peas beyond what's normal once the heat sets in.

My Sugar Snap Peas are having the same problem. The lower leaves yellowed and then died. I also think that the overall color of the leaves and vines are a lighter green than should be.

My yield has been so-so. I get about a dozen or so pods a week. I don't think the heat is an issue .. it hasn't cracked 80 degrees yet.

I think I will give in and feed them with a fertilizer and see what happens.

Here is a link that might be useful: My SFG Blog

I sowed peas a week ago - I know its late. Its sound like its hopeless, huh? We have had a cold snap. I'm in Buffalo - 6a

no, it's not necessarily hopeless, Janeccameron, just low probability ;-)

Seed is cheap and if you don't require the space for something else there is little to lose.

Peas don't necessarily 'melt' in warm weather they simply become much more susceptible to health problems as they don't grow well in the heat. If your temps go to the 90s consistently you have little hope, but who knows what the next couple months will bring?

Some people (not me though) have reported peas shutting down in summer, but remaining healthy. They are cut down to a few inches and regrow and in the fall as cooler weather returns, they start producing.

You just never know what will happen until you try ;-)

We've had 85-95 degree weather here in NC for weeks but my sugar snap peas have been doing fine -- I have them situated so the roots get lots of shade from other plants, especially in the afternoon.
Try to plant fast growing, sun loving annuals that are pretty good sized already all around the pea plants - you'll be surprised at how much better they look. Also, mulching the peas will help to keep them cooler.

Thanks so much. Reassuring. Its true - its all a bold experiment.

I wouldn't mulch until they've sprouted, right? They're next to some strawberries, that are pretty far along, with indeterminate tomato seedlings on the other side. I do have marigolds growing, but I have other herbs and annuals I could put in -good idea.

I fed the snap peas with a liquid fertalizer on Wed. 6/6/07. Do you think there is any hope that they will recover. I'm a little surprised that they have gone brown this early. The average temperature has been in the low 70s.

Here is a link that might be useful: My SFG Blog

I'm no expert, but it looks like fusarium wilt or root rot(particularly jamaellis picture). You can get seed that resists the disease, but I don't think there's much you can do once it gets that bad. It looks like you have peas, so it might not be that; after a couple harvests the peas just start to die. Peas are very light feeders and you shouldn't need to fertilize them much.

Last year, as soon as my peas started to yellow at the bottom, I buried the yellow with some fresh (and lightly fertilized) soil and topped the hill around the base of the vine with mulch. This seemed to work for a bit. I kept piling until I could pile no more and my peas made it until about august when it got above the 90s consecutively. Right after they died (for sure) the weather cooled almost immediately! I wonder how long this will work this year....
I also pick the peas prematurely since I love to eat the pods more than the actual peas. I like to think that harvesting the vines early, keeps the peas coming! This year I was able to get everything in early and the vines are easily twice as tall (taller than me at 5' 4") and producing well. I have already started my piling on a couple of them that get quite a bit of sun during the day. It may be too late for yours but if you want, plant some more right before it starts to cool off and try again! I used the same seeds as you and they did well.