Diuraphis mexicana (Brome grass aphid) identification, images, ecology, control

Adult apterae of Diuraphis mexicana (see first picture below) are pale yellow-brown to pale green with a pale brown head and appendages, and are wax-powdered. Their antennae are shorter than the body, with the terminal process 0.9-1.25 times the base of antennal segment VI (cf. Diuraphis meuhlei, which has the terminal process 1.2-1.65 times the base, or down to 1.0 in summer dwarfs). The length of hairs on antennal segment III is approximately 0.5 times the diameter of its base (cf. Diuraphis calamagrostis in Europe, which has these hairs only slightly less than the diameter of the base). The rostrum extends to the middle coxae with the apical rostral segment shorter than the second hind tarsal segment (HTII). Abdominal tergites III-V (sometimes also II and VI) have small marginal tubercles (cf. Diuraphis frequens, which has marginal tubercles absent). Abdominal tergite VIII has a short, broadly triangular supracaudal process (cf. Diuraphis noxia & Diuraphis meuhlei, which both have a longer finger-like process on tergite VIII). The siphunculi are short, without an apical flange (cf. Diuraphis mexicana Diuraphis noxia, which has an apical flange on the siphunculi). The cauda is elongate, triangular with a pointed apex, and usually with 4 lateral hairs. The body length of adult Diuraphis mexicana apterae is 1.4-2.0 mm.

Diuraphis mexicana (brome grass aphid) adult aptera on grass in Colorado, USA; Frank Peairs

Images copyright Frank Peairs, Colorado State University, Bugwood.org under a creative commons licence.

The alate Diuraphis mexicana has antennae shorter than the body, with 4-7 secondary rhinaria distributed in a straight row on antennal segment III, 0-2 on segment IV, and none on segment V. The wings have the veins fuscous bordered. The abdominal dorsum has no scleritized patches or bands.

Colonies of Diuraphis mexicana feed on open or rolled leaves of brome grass (Bromus) species, especially mountain brome (Bromus marginatus), cheat grass (Bromus tectorum) and California brome (Bromus carinatus), as well as on orchard grass (Dactylis glomerata). Aphid colonies may occur on open leaves or within rolled leaves, with feeding damage expressed as yellow streaking on light green leaves. In Mexico and California the species is mainly anholocyclic, but it is thought to be monoecious holocyclic further north (see picture of egg above). Diuraphis mexicana is found in Mexico, Western USA and British Columbia, Canada.

Other aphids on the same host

Diuraphis mexicana has been recorded on 6 Bromus species (Bromus carinatus, Bromus catharticus, Bromus marginatus, Bromus polyanthus, Bromus proximus var genuinus, Bromus tectorum).

Blackman & Eastop list 9 species of aphid as feeding on cheatgrass (Bromus tectorum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 5 as occurring in Britain (Show British list).
Blackman & Eastop list 5 species of aphid as feeding on mountain brome (Bromus marginatus) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 1 as occurring in Britain (Show British list).

Diuraphis mexicana has been recorded on 1 species of Dactylis (Dactylis glomerata)

Blackman & Eastop list 42 species of aphid as feeding on cocksfoot grass (Dactylis glomerata) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 34 as occurring in Britain (Show British list).

Acknowledgements

We are grateful to Frank Peairs, Colorado State University for making pictures of Diuraphis frequens available for use under a creative commons licence.
We have used the keys and species accounts of Miller et al. 2005 and Puterka et al. (2010) along with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors and those listed in the reference sections as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure provided by Blackman & Eastop (2006).

Useful weblinks

References

Miller, G.L. et al. (2005). A systematic reappraisal of the genus Diuraphis Aizednbderg (Hemiptera: Aphididae). Proc. Entomol. Soc. Wash. 107(3), 700-728. Full text
Puterka, G.J. et al. (2010). Host associations and incidence of Diuraphis spp. in the Rocky Mountain Region of the United States, and pictorial key for their identification. Journal of Economic Entomology 103(5), 1875-1885. Full text

Diuraphis mexicana

Brome grass aphid

Identification & Distribution

Other aphids on the same host

Acknowledgements

Useful weblinks

References