I don't know if they are sick and diseased, but I suspect they haven't liked the periodic cold weather we've had since you planted them. That is why their growth seems slow---they like hot weather and grow like mad when it is hot. When we keep getting late cold weather recurring a day or two a week, like we have had in April and May the last few years, southern peas planted a bit early won't necessarily die, but they'll just sit there and not look particularly happy. Sound familiar?

I tend to plant southern peas really late---usually no earlier than mid-May in an average year. Partly that's because I always find myself waiting for a cool-season crop to finish up so I'll have space to plant a hot-season crop, and partly it is because we keep having very cold nights even into early May, and southern peas exposed to cold temperatures seem to have more trouble with pests and diseases.

It doesn't look like mosaic to me. It looks like plants that are struggling with the environment---think of all they have been exposed to since you planted them---some really cold nights, some very hot, drying, ridiculously windy days, and far less moisture than young plants like and need. What they need most is for the weather to stabilize and stay nice and warm, with occasional rain.

It always amazes me how quickly southern peas grow in the kind of weather they prefer, as well as how much they can sulk and pout when they are too cold.

Just relax and ignore them. Let them pout their way through these next couple of cool to downright cold nights and fairly pleasant days. In a few days, our blast furnace temperatures will return and it is likely they'll perk right up and grow well.

I started most of my hot pepper plants late and they have remained smallish and slow-growing. Finally, in the last week we hit the kind of blistering hot days/warm nights that they like without any cold nights dropping into the picture and they have responded by doubling in size seemingly overnight. Now, we're about to have overnight lows in the mid to low-40s for a couple of nights. I can guarantee you that my hot pepper plants won't care for those temperatures, and neither will your southern pea plants, but they'll survive. They'll perk up again and grow more as soon as it gets nice and hot again, particularly if rain falls a little here and there.

Do keep an eye on the underside of the southern pea plants' leaves. Aphids love to feast on them and aphids can spread viral diseases. Usually the southern pea plants shrug off the diseases and produce well anyhow, but if they already are stunted and growing slowly, it can be harder for them to fight through an aphid infestation and the diseases that often follow.

I don't worry much about the appearance of southern pea foliage. Lots of pests are attracted to the foliage and it can go from a beautiful deep green to something much less beautiful fairly quickly. The thing to remember is that we don't grow them for their foliage---we grow them for the peas themselves.

Finally, if you are growing them in a place where you haven't grown legumes before, I hope you inoculated then with an inoculant formulated for that type of legume. The inoculant helps them to fix nitrogen and really does seem to improve their growth and performance.

Nope, did not inoculate them. Any recommended inoculant?

I'll try to relax and ignore them. It bothers me because the beans (McCaslan, Rattlesnake, Contender and Kebarika) are right beside them and are looking great.

Beans tolerate colder weather better than southern peas do. Southern peas like it hot!

There's no specific brand of inoculant that I use regularly. You just have to buy one that is formulated for legumes. I'll link an example of one that is a combination product that works for most anything you'd need to inoculate here. Inoculant is not necessarily easy to find in stores. I usually order some from one of the seed companies when I am ordering seeds in winter for the upcoming planting season. It has an expiration date so I don't order it in gigantic amounts.

Not inoculating is not the worst thing in the world. I just feel like I have gotten better yields when I do it. You don't have to inoculate if any legume has been grown in that soil before because the nitrogen-fixing rhizobia will already be there in the soil.

Here is a link that might be useful: Example of a Legume Inoculant Product