Asphondylia ambrosiae

Contarinia partheniicola (on Ambrosia)

Neolasioptera ambrosiae

Rhopalomyia ambrosiae

Contarinia partheniicola (on Parthenium incanum)

A. ambrosiae forms fuzzy, globose bud galls on Ambrosia spp. Pupation takes place within the galls.


*Contarinia partheniicola*

*Contarinia partheniicola* forms whitish, woolly, cupulate galls 5-8 mm long and 4-5 mm wide. Previously reported only from *Parthenium, incanum*, the type host, it is now known to occur on *Ambrosia* spp....R. D. Goeden writes (pers. comm.) that the galls on *Ambrosia* are formed singly or in small groups on various parts of the shoots, e.g., on axillary buds along the stems, on the young leaves, on the staminate florets, and along the rachis of the inflorescence.

Neolasioptera ambrosiae

N. ambrosiae is hard to find because there is usually no apparent gall or only the slightest swelling; occasionally, it causes a noticeable fusiform swelling on the small side branchlets. One to several larvae occur in a stem where they crawl up and down silken tubes where the pith would normally be. Before pupation, the larva cuts a hole almost all the way through the twig and retracts into the pith, where it overwinters. In spring the larva pupates, and the adult emerges a short time later.

Rhopalomyia ambrosiae

CE Stegmaier, Jr writes that R ambrosiae forms a bud gall on the terminal tips of A artemisiifolia. 

Contarinia partheniicola

Contarinia partheniicola forms whitish, woolly, cupulate galls 5-8 mm long and 4-5 mm wide. Previously reported only from Parthenium, incanum, the type host, it is now known to occur on Ambrosia spp....R. D. Goeden writes (pers. comm.) that the galls on Ambrosia are formed singly or in small groups on various parts of the shoots, e.g., on axillary buds along the stems, on the young leaves, on the staminate florets, and along the rachis of the inflorescence.

The gall midges of ragweed, Ambrosia, with descriptions of two new species (Diptera: Cecidomyiidae)