The genus Botrytis consists of several fungal pathogens known to be highly destructive to agriculture worldwide. Common species of Botrytis can infect a variety of hosts, and while some species are more host-specific, their potential host ranges are not well studied. As one of many mechanisms underlying host-pathogen ranges, we use a comparative genomics approach centering on primary metabolism to describe variation amongst Botrytis species with variable host ranges. We constructed individual de novo metabolic models to assess growth-rate variation under controlled resource-rich conditions and constructed a pangenome of 16 fungal species to assess the presence or absence of orthologous primary metabolic genes. We concluded that Botrytis cinerea had the fastest growth rate of our metabolic models and found about 30,000 orthologous genes across the genus with the pangenome. Our results serve to suggest possible new host ranges for host-specific species.