Diplodia black storage rot

The disease is caused by the fungus Botryodiplodia theobromae (Diplodia tubericola). It affects sweet potatoes in storage. The inner part of the infected edible root becomes black and brittle. Many tiny black fungal bodies (pycnidia) form just below the sweet potato skin giving the root a pimply appearance. Infection occurs through broken ends and abrasions on storage roots. Wet conditions favour disease spread and development.