Detection and Identification of <i>Botrytis</i> Species Associated with Neck Rot, Scape Blight, and Umbel Blight of Onion

Fig. 5A. Onion seed assayed for Botrytis spp. on Kritzman’s agar (22). (A, shown here) Concentric rings of sporulation with darkening of the agar medium resulting from polyphenoloxidase (PPO) activity of B. allii or B. aclada.



Image from Plant Health Progress article:
Detection and Identification of Botrytis Species Associated with Neck Rot, Scape Blight, and Umbel Blight of Onion