Udea adversa is a moth in the Crambidae family. It was described by Philpott in 1917. It is found in New Zealand. The wingspan is 20–21 mm for males and females. The forewings are ferruginous, but brighter along the costa. There is an irregular transverse outwardly-oblique white discal dot at the middle and a dark, obscurely indicated second line. The hindwings are yellow with the discal dot and terminal band fuscous.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0