Agromyza ambrosivora Spencer,

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: 7-8

publication ID

publication LSID

persistent identifier

treatment provided by


scientific name

Agromyza ambrosivora Spencer


Agromyza ambrosivora Spencer 

( Fig. 64View FIGURES 63–74)

Material examined. COLORADO: Chaffee Co., Poncha Springs  , South Arkansas River, 8.vii.2015, em  . 28.vii – 1.viii.2015, C.S. Eiseman, ex Helianthus annuus  , #CSE1872, CNC654328–654332 (1♂ 4♀); MASSACHUSETTS: Worcester Co., Sturbridge, Leadmine Rd. , 6.vii.2013, em  . 20.vii.2013, C.S. Eiseman, ex Ambrosia artemisiifolia  , #CSE725, CNC392679View Materials, CNC392680View Materials (2♀); PENNSYLVANIA: Chester Co., Pottstown   , Warwick County Park , 10.viii.2014, em  . 2.ix.2014, N. D. Charney, ex Ambrosia trifida  , #CSE1371, CNC384846 (1♂).

Hosts. Asteraceae  : Ambrosia artemisiifolia  L., A. * trifida  L., * Helianthus annuus L. Some  specimens from Los Angeles and Ventura Counties, California, were caught at sites where Artemisia douglasiana Besser  was one of the dominant plants, and Spencer (1981) stated that it therefore seems probable that this was the host. He noted that Ambrosia  is not known in these counties, but the genus is now known from both counties and several Helianthus  species are also present (USDA, NRCS 2017).

Leaf mine. ( Fig. 64View FIGURES 63–74) On Ambrosia artemisiifolia  , “several larvae frequently feeding together to form a blackish leaf-mine, which extends from the apex of the pinnately divided leaves towards the midrib” ( Spencer 1969). In our example the apices of three lobes were disfigured by the mine. The mine on A. trifida  was a brown blotch in the angle between the midrib and a lateral vein; there was a narrow initial linear portion that had been mostly obliterated. The mines on Helianthus  ( Fig. 64View FIGURES 63–74) began near the leaf margin in the basal half of the leaf blade and followed the margin apically, widening gradually.

Puparium. Brown; formed outside the mine.

Distribution. USA: CA, *CO, *MA, MD ( Scheffer et al. 2007), NY ( Scheffer & Lonsdale 2018), *PA; Canada: ON.