Identification of the etiological agent for necrotizing scute disease in the Texas tortoise

Epidermal lamellae (scutes) of the Texas tortoise, Gopherus berlandieri, from southern Texas (USA) were observed to be in various stages of necrosis, ranging from localized whitish blemishes to complete degradation of the external portion of the scute. Fusarium semitectum was consistently isolated from slivers of infected scute from tortoises. The fungus was not isolated from tortoises exhibiting no lesions. Confocal microscopy confirmed the presence of septate mycelia inside the scutes, and isolates of F. semitectum grown in the laboratory were successfully transferred to non-infected tortoises. Twenty-four tortoises maintained by two rehabilitators in southern Texas exhibited lesions; however, only one of 27 tortoises from Dimmit and Zavala counties was infected.