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Aphidinae : Macrosiphini : Nasonovia crenicorna


Nasonovia crenicorna

Hairy-cornicled geranium aphid

On this page: Identification & Distribution Other aphids on the same host

Identification & Distribution

Adult apterae of Nasonovia crenicorna (see first picture below of fundatrix) are light green with a faint dark spinal stripe. The antennae are dark or greenish brown except segment I and the base of segment III. The siphunculi and cauda are very light greenish-brown, and the siphunculi have dark apices. The antennae are 0.8-0.9 times the body length, with the terminal process 4.3-5.6 times the base of segment VI. There are 4-18 very small secondary rhinaria on the basal 0.67 of segment III, with none on IV or V. The longest hair on antennal segment III is 0.85-1.1 times the basal diameter of that segment. The apical rostral segment is 1.8-2.0 times the second hind tarsal segment, with about 30 accessory hairs. The abdominal tergites bear numerous blunt or slightly capitate hairs. There are rather indistinct marginal tubercles present on the prothorax and tergites II-V, although some may be absent. Tarsal segment I has 2 or 3 hairs. The siphunculi are 1.9-2.2 times the cauda, with a distinct, well developed flange, and below this sometimes some polygonal reticulation. The siphunculi are unusual in bearing 5-11 blunt or capitate hairs on the basal 0.67 (just visible in the picture below). The cauda is tongue-shaped, with 16-20 rather short hairs. Body length of the adult Nasonovia crenicorna aptera is 3.5-5.1 mm.

Images above copyright Andrew Jensen under a creative common licence.

The alate vivipara of Nasonovia crenicorna is coloured like the aptera with a pale green abdomen. The antennae are 0.9-1.2 times the body length and bear 12-23 secondary rhinaria on antennal segment III, and none on segments IV & V. The siphunculi are more or less cylindrical, 1.7-2.0 times the cauda and, like the aptera, bear 6-11 hairs, in this case on their basal 0.33-0.67. The cauda has 16-23 hairs.

Nasonovia crenicorna is monoecious on Richardson's geranium (Geranium richardsonii) and sticky purple geranium (Geranium viscosissimum). It is holocyclic, with oviparae and alate males in July-August. The species produces the sexuales fairly early in the year (July-August) to fit with the life cycle of the plant. It is found in western USA.


Other aphids on the same host

Nasonovia crenicorna has been recorded from 2 Geranium species (Geranium richardsonii, Geranium viscosissimum).


We are grateful to Andrew Jensen for making his image of Nasonovia crenicorna available for use under a creative commons licence.

We have used the species accounts given by Smith and Knowlton (1939) & Palmer (1952) (both as Macrosiphum crenicornum) & Heie (1979), together 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 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


  • Heie, E.O. (1979). Revision of the aphid genus Nasonovia Mordvilko, including Kakimia Hottes & Frison, with keys and descriptions of the species of the world (Homoptera: Aphididae). Entomologica Scandinavica Supplement 9, 105 pp.

  • Palmer, M.A. (1952). Aphids of the Rocky Mountain Region: including primarily Colorado and Utah, but also bordering area composed of southern Wyoming, southeastern Idaho and northern New Mexico. Full text

  • Smith, C.F. & Knowlton, G.F. (1939). Three intermountain aphids. The Canadian Entomologist 71, 241-243.