Not usual to have black root rot (BRR) post in late season diseases, but we see more often of BRR pathogen colonising & blackening woody tissue. Would be useful if we can understand the infection from the epidermis on seedlings to the pith of mature plants.

On seedlings, BRR-infected epidermal tissue is often sloughed off when the growing conditions become warmer and plants grow bigger (noticing to cracking zones).