We compared the degradative enzymology of fusaria in a small clade of closely related species as determined by phylogenetic analysis of nuclear 28S rDNA sequences. The clade includes entomogenous species and at least one recently discovered lichenicolous species. The lichenicolous Fusarium sp. and three entomogenous species were tested for the ability to degrade lichen tissue in both the presence and the absence of antibiotic secondary compounds. Only the undescribed lichenicolous Fusarium sp. showed degradative ability irrespective of lichen secondary chemistry and this was correlated with its ability to hydrolyse enzymatically the antibiotic depside, lecanoric acid. Similarly, the lichenicolous Fusarium sp. exhibited the greatest capacity for degrading lichen cell walls and the highest levels of cell wall-degrading polysaccharidases. These results correlate the ability to exploit lichen substrates with the production of specific enzyme activities able to overcome the chemical and physical barriers that characterize lichen hosts.