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Aphidinae : Aphidini : Aphis varians
 

 

Aphis varians

Variable currant aphid, White-cornicled currant aphid

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

Identification & Distribution

Adult apterae of Aphis varians (see two pictures below) are dark blue-green to greenish-brown or orange-brown with a rather uniform powdering of wax; the siphunculi are pale and the cauda is mainly dark or dusky. The hairs on antennal segment III are very long, fine & wavy, 1.8-4 times the basal diameter of that segment (cf. Aphis epilobii and Aphis oenotherae, both in Europe & USA, which have those hairs only 1-2 times the basal diameter). The antennal terminal process is 1.5-2.0 times the base of antennal segment VI (cf. Aphis epilobii & Aphis oenotherae, which both have the terminal process more than 2 times the base of that segment). The apical rostral segment (RIV+V) has 6-12 accessory hairs (cf. Aphis praeterita, Aphis frangulae, Aphis asclepiadis & Aphis gossypii, which all have only 2 accessory hairs on RIV+V). There are marginal tubercles on abdominal tergites I & VII, but tergites II-V only sporadically have small marginal tubercles (cf. Aphis schneideri in Europe & Asia, which has well-developed marginal tubercles on all abdominal tergites other than VI). The siphunculi are milky-white, with dusky tips, and the cauda is dark or dusky. The body length of adult Aphis varians apterae is 1.0-2.2 mm. Immatures are dull green.

First image above copyright M. Alex Smith, CBG Photography Group,
second image copyright Andrew Jensen, both under a cc by-nc-sa licence.

The alate Aphis varians (see clarified mount below) has the head and thorax black, and the abdomen dark green, with transverse dark bands on the posterior segments. The siphunculi and the cauda are dark. There are 20-30 secondary rhinaria on antennal segment III, about 15 on segment IV and a few on segment V.

Image above copyright CBG Photography Group under a cc by-nc-sa licence.

Aphis varians is found on the spring growth of currants (Ribes spp.), where it crumples the leaves and stunts growth. The species is heteroecious holocyclic, migrating in late spring to willowherbs (Onagraceae), especially fireweed (Epilobium angustifolium). It is attended by ants. Aphis varians is found throughout North America. There are records of Aphis varians from Mongolia and east Siberia, but these are likely misidentifications (see Aphids on World Plants).

 

Other aphids on the same host

Primary hosts:

Aphis varians has been recorded on 6 species of currant (Ribes diacanthum, Ribes fragrans, Ribes magellanicum, Ribes nigrum, Ribes triste, Ribes uva-crispa).

Secondary hosts:

Aphis varians has been recorded on 3 species of willowherb (Epilobium) (Epilobium angustifolium, Epilobium coloratum, Epilobium palustre).

 

Damage and control

Despite Patch (1927) describing Aphis varians as one of the most abundant and destructive species on currant bushes, remarkably little seems to have been written in recent years about control of this particular species. More emphasis is generally put on control of another common currant aphid, Cryptomyzus ribis.

Acknowledgements

We are grateful to Andrew Jensen and M. Alex Smith, CBG Photography Group for making their pictures available for use under creative commons licences.

We have used the keys and species accounts of Patch (1914) and Patch (1927) 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

  • Patch, E. (1914). Currant and gooseberry aphids in Maine. Bulletin of the Maine Agricultural Experiment Station 225, 49-60. Full text

  • Patch, E. (1927). Two currant aphids that migrate to willow-herbs. Bulletin of the Maine Agricultural Experiment Station 336, 1-8.