I put down some pea straw as mulcha couple of months ago and had nice little pea sprouts popping up from the seeds in it. Also, i planted some telephone pea plants.
Both have since started getting brown blemishes on their leaves and stems - worse closer to the ground - i have attached a photo from both types of plants.
There is little if any sun on this part of the garden now the seasons are changing so i don't expect much from the pea plants, however i just want to make sure this does not reflect a desease that needs treating, so next spring my garden can be all ready to go!
It will be a fungal infection from the pea straw, most likely. Because the pea straw is basically rooting pea plants, it is not a good idea to use it where you plan to grow peas. Unfortunately, you will probably need to wait for at least a full year for the straw to rot out fully and fungus to die out naturally before you can grow peas successfully.
I also learnt that one the hard way.
The best option is to keep some garden aside for peas that never gets mulched with pea straw.