Citron
The citron ("Citrus medica") is a large fragrant citrus fruit with a thick rind. It is one of the original citrus fruits from which all other citrus types developed through natural hybrid speciation or artificial hybridization. Though citron cultivars take on a wide variety of physical forms, they are all closely related genetically. It is used widely in Asian cuisine, and also in traditional medicines, perfume, and for religious rituals and offerings. Hybrids of citrons with other citrus are commercially prominent, notably lemons and many limes.
Mal secco
The main host of mal secco is the lemon; however other genera including Citrus, Severina, Fortunella, and Poncirus have all been reported to be susceptible. In addition to lemon, the disease has been observed to be highly destructive in Citron (C. "medica L".), lime (C. "latifolia Tan".), and bergamot (C. "bergamia Risso"). The most common lemons in the Mediterranean, the rough lemon (C. "jambiri Lush"), volkamer lemon (C. "volkameriana Ten. & Pasq".), and alemow (C. "macrophilla wester") are very susceptible.