Phytomyza syngenesiae (Hardy)

Eiseman, Charles S. & Lonsdale, Owen, 2018, New state and host records for Agromyzidae (Diptera) in the United States, with the description of thirty new species, Zootaxa 4479 (1), pp. 1-156 : 84-85

Phytomyza syngenesiae (Hardy)

( Fig. 208 )

Material examined. MASSACHUSETTS: Nantucket Co., Nantucket , 2 Milk St. , 10.vi.2016, em . 22–29.vi.2016, C.S. Eiseman, ex Tanacetum parthenium , #CSE2612, CNC634774–634776 (3♂); same location, 11.vi.2016, em . 23.vi.2016, C.S. Eiseman, ex Leucanthemum vulgare , #CSE2619, CNC635235, CNC635236 (2♀); Liberty St. (41.283729, -70.103993), 31.vii.2017, em . 2–4.viii.2017, C.S. Eiseman, ex Sonchus asper , #CSE4055, CNC939655–939659 (2♂ 3♀).

Hosts. Apiaceae : Daucus carota L. ( Smulyan 1914); Asteraceae : Ambrosia artemisiifolia L. ( Frick 1959), A. psilostachya DC. ( Goeden and Ricker 1976), Antennaria plantaginifolia (L.) Richardson ( Frick 1959), Argyranthemum frutescens (L.) Sch. Bip. ( Frick 1959), Artemisia vulgaris L. ( Frick 1959), Bidens frondosa L. ( Frick 1959) , Carduus pycnocephalus L. ( Frick 1959), Chrysanthemum L. (cultivated variety), C. ×morifolium Ramat. ( Frick 1959), Crepis L., Cynara scolymus L., Dahlia Cav. , Delairea odorata Lem. ( Frick 1959) , Dendranthema indicum (L.) Des Moulins ( Frick 1959), “eupatoriums” ( Falconer 1887), Gazania Gaertn. ( Falconer 1887) , Helianthus annuus L. ( Smulyan 1914) , H. californicus DC., H. ×multiflorus L. ( Falconer 1887), Lactuca L., Leucanthemum vulgare Lam. ( Frick 1959; present study), Matricaria L. (cultivated variety), Packera indecora (Greene) Á. Löve & D. Löve ( Griffiths 1974c) , Parthenium argentatum A. Gray ( Frick 1959), Pericallis hybrida B. Nord., Petasites Mill. ( Frick 1959) , Picris echioides L., Senecio jacobaea L. ( Frick 1972), S. vulgaris L. ( Griffiths 1974c), Silybum marianum (L.) Gaertn., Smallanthus uvedalius (L.) Mack. ex Small ( Spencer & Steyskal 1986), Solidago nemoralis Aiton ( Smulyan 1914) , Sonchus asper (L.) Hill, S. oleraceus L., Tanacetum parthenium (L.) Sch. Bip. ( Falconer 1887; present study), T. vulgare L. ( Lintner 1888), Taraxacum officinale F.H. Wigg. ( Frick 1959) , Zinnia violacea Cav. ; Fabaceae : Melilotus indicus (L.) All. ( Frick 1959), Pisum sativum L.; Lamiaceae : Mentha L. ( Frick 1959), Stachys bullata Benth. ( Frick 1959) , Malvaceae : Malva nicaeensis All. ( Frick 1959) .

Except where indicated, Griffiths (1967) verified the above records by examination of genitalia of reared males. Griffiths (1977) stated that Sehgal’s (1971) record from Crepis gracilis (D.C. Eat.) Rydb. (= C. atribarba A. Heller ) probably involved a misidentified plant because the only species of Crepis confirmed from the Edmonton, Alberta area are C. runcinata (James) Torr. & A. Gray and C. tectorum L. The records of Frick (1959) all appear to represent reared specimens examined by him. Griffiths (1967) considered Frick’s list generally to be attributable to Phytomyza syngenesiae , but he noted that the series Frick reared from Pseudognaphalium leucocephalum (A. Gray) Anderb. (Asteraceae) in California “does not represent a species of the syngenesiae group, but a species related to the European Phytomyza ciliata Hendel and P. farfarae Hendel. ” Spencer (1981) made no reference to these flies, and the species apparently remains undescribed. Griffiths (1972b) also cautioned that the record of Petasites requires confirmation due to possible confusion with other species found on this host. Griffiths (1967) further stated that “confirmation from the dissection of males bred from [the non-Asteraceae] hosts seems desirable before they can be finally accepted.” He did verify a California specimen reared from Pisum sativum as well as one reared from Daucus carota in Denmark. The records of Falconer (1887), Lintner (1888), and Smulyan (1914) are from greenhouses in New York and Massachusetts. The origin of the Smallanthus uvedalius record is unclear, as Spencer & Steyskal (1986) do not mention having examined any specimens of P. syngenesiae , and the only distribution records they cite are those listed by Frick (1959), none of which are within the known range of this plant.

Leaf mine. ( Fig. 208 ) White, entirely linear, with frass mostly in discrete black grains along the margins; largely on the upper surface, but with the final stretch on the lower surface.

Puparium. White to yellow; formed within the mine, its anterior spiracles projecting ventrally through the lower (or sometimes the upper) epidermis.

Distribution. USA: CA, MA, OR ( Frick 1959), RI, WA; Canada: AB, BC ( Frick 1959); Colombia? ( Spencer 1984); Europe; Sri Lanka ( Wijesekara 2002); Japan; Kenya ( Černý & Tschirnhaus 2014); Australia; New Zealand. The preceding North American records were all verified by Griffiths (1967) except where indicated. See further notes on distribution below.

Comments. This species is apparently native to Europe and introduced elsewhere with horticultural plants. The earliest North American records, as summarized by Smulyan (1914), are all from greenhouses in the northern USA: NY (1886, Glen Cove), PA (1887, Germantown), MA (1889, Boston area), CT (1890, Danbury), NH (1907), MT (1912, Helena), WI (1912, Milwaukee), and IL (1912, Chicago). The RI specimens cited by Griffiths (1967) were reared in 1910 and 1916.

Studying an infestation near Boston, MA, Smulyan (1914) found no evidence of the flies spreading to outdoor plants beyond the immediate vicinity of the greenhouse. The only recent (post 1916) evidence of Phytomyza syngenesiae we have found in the northeastern USA are our own observations on Nantucket Island, MA. Mines are reliably found on Tanacetum and Leucanthemum in a garden next to the Maria Mitchell Natural Science Museum, which is a sheltered area in a heavily human-altered environment but there is no greenhouse nearby. We have surveyed the island extensively for leafminers, and the only other apparent mines of P. syngenesiae we have found are a few on Arctium L. and Sonchus asper , likewise near roads and human structures, along with a single example on Erechtites hieraciifolius (L.) Raf. ex DC., collected 4 August 2012 at Almanac Pond, a natural area far from any human structures. Mines on all three hosts contained puparia, but adults were only reared from Sonchus .

Phytomyza syngenesiae does appear to be established along the Pacific Coast. We have found mines on Sonchus oleraceus on a beach in Washington, and mines have been photographed on this host in an urban alley in San Francisco ( Pearson 2011) and on a weedy plant resembling Sonchus on a beach in Los Angeles ( Mallory 2011).

Figures

FIGURES 208–216. leaf mines; 208: Phytomyza syngenesiae (Hardy) in Tanacetum parthenium; 209: P. tarnwoodensis spec. nov. in Diervilla lonicera; 210: P. thalictrivora Spencer in Thalictrum pubescens; 211: P. tigris spec. nov. in Tiarella cordifolia; 212: P. triangularidis spec. nov. in Senecio triangularis; 213: same; 214: P. vancouveriella spec. nov. in Ƒancouveria hexandra; 215: P. verbenae spec. nov. in Ƒerbena lasiostachys; 216: P. ziziae spec. nov. in Zizia aurea (dark brown puparium on leaf surface, near margin).