Nemorimyza maculosa

Nemorimyza maculosa (Malloch, 1913)

This species was recently transferred from Amauromyza to the genus Nemorimyza Zlobin, 1997.
The male genitalia of N. maculosa are distinct. Material collected from potential host plants can be also identified by the combination of the presence of prescutellar bristles (prsc id.pct) and the Phytomyzinae-like wing vein pattern (agr-phy-wing.pct).

Wing length: 2.3 - 2.5 mm. Frons and lunule black; prescutellar bristles present. The two inwards directed frontorbital bristles are conspicuously shorter than the other frontorbitals.
Male terminalia
Hypandrium short with short hypandrial apodeme. Ejaculatory apodeme asymmetrical with base not bowl shaped. (Material from BMNH with bowl shaped ejaculatory apodeme). Epandrium long, regularly covered with longer hairs. Surstyli fully separated from the epandrium, basally not fused with the 9th sternite. Gonites dark, located besides an appendix of the hypandrium (pregonite). Distiphallus with large lobe and two appendages at its base. Terminal tubules of distiphallus distally widely apart.
Immature stages
Anterior spiracles strongly asymmetrical, directed mainly to posterior direction. Presumably numerous terminal bulbs in one row. Posterior spiracles strongly projecting with each three well visible spiracular openings of identical size, once again similar to Nemorimyza posticata. The locomotion welts on the borders of the segments are restricted to the sides, however, on the dorsal surface the whole segments are sparsely covered with small denticles. Last segment covered with denticles, particularly below the spiracles.
Cephalopharyngeal skeleton: Generally almost identical as posticata. Mandibles with each two non alternating short hooks; Middle furrow of face clearly visible; intermediate sclerite short relative to basal part, of normal shape, well separated from the latter.

The larvae produce large blotch mines on the leaves, pupariation takes place in the soil.

Lactuca sativa (lettuce) is considered as the main host. In Florida also the following genera of ornamental plants are recorded: Baccharis, Bidens, Chrysanthemum, Erechitites, Emilia, Eupatorium, Gnaphalium, Gaillardia, Helianthus, Melanthera, Senecio, Sonchus, Tagetes (Stegmaier, 1967).

Widespread in South America, North America: Eastern part from Florida to New York, Hawaii. Can be sometimes imported to Europe through imported cutflowers (Spencer, 1973).

Amauromyza maculosa belongs to the EPPO (European Mediterranean plant protection organization) A1 Quarantine List.
The species can be considered as of minor importance, since serious mass outbreaks are not known. However, the rather large blotch mines damage especially young plants.