I don't know where you are. Or how much you know about walnuts.

Are you saying that the fruits on the outside are brown mush? Or that the inner nut meat, inside the hard inner shell, is brown mush?

Sorry if if this seems like a stupid question.....

When the nuts fall, remove the green husks and brown mushy pulp. Wear rubber gloves! The brown pulp was used as a very effective brown dye at one time. After removing the husks the nuts should "cure" before eating. If you crush the nuts with the husk still on it will be a mushy mess. It is a lot of work, but it is worth the effort.

tj

Here is a link that might be useful: Harvesting Walnuts

Interesting aside: I once had a dog who ate walnuts as soon as the green husk was gone. I don't know how she had any teeth left when she died after many years of this activitiy! Oh, she also ate a Rhododendron shrub to the ground...and I did feed her!

I have tried opening both green and older black nuts but they are mush inside...disease? Do they just need to cure?

If the nuts themselves are mush, then this may really indicate a problem. Depending on where you are, it may be weather. But if I were you, I would repost the basic info, with the fact that it is the nuts themselves that are mush, and the fact that they were like this in both late July and late August, to the trees forum.

There are many tree experts that do not always follow the woodlands forum.....

I heard that when they lact of some nutrition,something happen like what you said .But sorry I don't what kind of it .