Holly
Guides
Phytomyza
Phytomyza is a genus of leaf-mining flies in the family Agromyzidae, comprising at least 170 described species. Larvae develop as miners within living plant leaves, creating distinctive serpentine or blotchy galleries between the upper and lower epidermis. Adults are small, typically black or dark-colored flies resembling tiny houseflies. The genus exhibits high host specificity, with individual species often restricted to particular plant genera or families.
Phytomyza glabricola
inkberry holly leafminer
Phytomyza glabricola is a leaf-mining fly in the family Agromyzidae, endemic to the eastern United States. The species exhibits host-associated divergence on two sympatric holly species, Ilex glabra and I. coriacea, with populations on each host showing substantial genetic divergence and reproductive isolation. Development time differs dramatically between host races: 2-4 weeks with multiple generations per year on I. glabra versus 9-10 months with a single generation per year on I. coriacea. Despite these differences, adults from both hosts emerge synchronously in mid-January to mid-February. The species provides a well-documented case of ecological speciation via host shift.
Phytomyza hatfieldae
Phytomyza hatfieldae is a leaf-mining fly in the family Agromyzidae, described in 2018. Like other Phytomyza species, it likely produces serpentine leaf mines on host plants. The species is closely related to and potentially confused with the native holly leafminer (Phytomyza ilicicola), from which it may be distinguished by host plant associations and subtle morphological differences.
Phytomyza opacae
Native holly leafminer
Phytomyza opacae is a leaf-mining fly in the family Agromyzidae. It is a specialist herbivore that develops within the leaves of holly species (Ilex). The larva creates distinctive serpentine mines visible on leaf surfaces. This species is closely associated with American holly (Ilex opaca) and related Ilex species.
Phytomyza sempervirentis
English Holly Leafminer
Phytomyza sempervirentis is a leaf-mining fly in the family Agromyzidae. The species was described in 2018 and is associated with Ilex species, including English holly (Ilex aquifolium). Larvae create serpentine mines within holly leaves, feeding between the upper and lower epidermis. Adults are small black flies that emerge in spring to coincide with the production of tender new leaves.