A Gardeners Forum Forums General Discussion The Food Garden Forum Dying Snow Peas

So far for the last week or so, one of my snow peas had started at the bottom of the plant to turn yellow and then progressed to the entire plant starting from the bottom and going upwards turning yellow including the stem. This is happening to one plant out of 6, four of the plants are perfectly fine, and two are not yellowing but have few small black spots on their leaves but is still flowering and producing peas.

I removed the yellow plant and inspected the the roots and noticed little nodules on the roots. I'm not sure if the plant is suppose to have those or not. The soil was originally sandy and loam and I amended the soil with miracle grow garden soil and for the last two months were fine. I'm not sure whats happening here.

Blight, fusarium wilt, mosaic virus, powdery mildew and root rot are the most common diseases of peas along with aphid infestation.

When it happens here it's usually Fusariam Wilt...happens alot when it's a wet season. It's a fungus..

The nodules come from some kind of nitrogen bacteria...not fully understanding of that though...

Yes, the nodules are beneficial and are present on all legumes.
One more thing to consider, haven't you had a heatwave on the East Coast? Peas can't tolerate heat.
Also....black specks are possible from honeydew produced by aphids. There will always be a few aphids on peas, but a number of them is bad news. A little insecticidal soap applied in the evening will take care of them, but careful not to kill ladybugs and their larva, they're there to eat the aphids.
tamara...legumes provide a place for nitrogen fixing bacteria to live, which take nitrogen from air and store it...the peas use it, and some is still there when the peas die off, so leaving the dead plants and turning them in adds nitrogen back to the soil. Legumes like peas, beans, vetch and alfalfa, I believe, can be used as a cover crop to enrich soil between plantings of other crops Some farmers grow mung beans and such after harvesting wheat so as to fix nitrogen in the soil.

Yes, we have been having mini heat waves on and off here in NY but I find it odd that only one plant would die so quickly out of so many thriving plants. I always thought heat only caused wilting of the plant and that after the wave is over, the plant will get better again, I didn't think they would die.

Can heat waves kill plants even though the are well watered multiple times a day during high temps? I also shade them during high temps.

I have bough some insecticidal soap for my peas today but have not used it yet. I think it might kill lady bugs but I'm not sure, I haven't seen anyone else on the plant, only the small black eggs which seem to be laid on more near the flower where the peas are emerging or inside the flower itself.

Should I still spray the plant even if I don't see the ladybugs?
I love ladybugs, I would hate to kill them.

Heat can kill peas outright, individuals can be weaker than their siblings...either way, it could be that your season is coming to a close for peas due to weather, but I don't have much experience to go by with peas, just a few attempts plus what I've read.
Watering is important but not nescessarily the same issue as heat itself, heat itself is the main issue with crops like peas.
Soap must contact and actually cover insects in order to kill them, so unless you see ladybugs when you spray, there is no problem. You should Google ladybug larva and get familiar with what they look like if you're not already familiar with them, they look like little Gila monsters, but they eat aphids 10 to 1 or more than adult ladybugs. Don't spray on hot, sunny days as that will cause severe damage (sunburn mostly, and suffocation of tissue) but wait until evening so the plants have all night to recover.
What you're seeing as "small, black eggs" is likely the excrement of aphids, insecticidal soap is an ideal control. Aphids excrete honeydew, which is clear, but quickly turns black due to bacteria and mold colonies.