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Identification & Distribution

Adult apterae of Aphis glycines (see first picture below) range from pale yellow to lime green in colour, commonly green mottled with pale yellow. On late season soybeans, some aphids may be much smaller and paler than usual. The insect's head is pale, as are the basal antennal segments, and the antennal tubercles are weakly developed. The siphunculi are dark except at their bases (cf. Aphis nasturtii which has the siphunculi usually rather pale, only darker at the apices). The cauda is very pale, usually with a slight midway constriction, more than 3 times longer than its narrowest width at midlength, and usually bearing 7-9 hairs (cf. Aphis gossypii for which the cauda is pale to dusky, without a constriction, less than 3 times longer than its width at midlength, and usually bearing 5-6 hairs). The body length of adult Aphis glycines apterae is 1.2-1.7 mm.

First image above copyright Ho Jung Yoo, Purdue University; all use allowed providing attribution given.
Second image above copyright Christina DiFonzo under a Creative Commons Attribution 3.0 United States license.

Both micrographs courtesy Favret, C. & G.L. Miller, AphID. Identification Technology Program, CPHST, PPQ, APHIS, USDA; Fort Collins, CO.

Aphis glycines is native to Asia where its main primary hosts are Dahurian buckthorn (Rhamnus davurica) and Japanese buckthorn (Rhamnus japonica). Aphis glycines host alternates mainly to soybean and other wild Glycine species, and a few other members of the Fabaceae. In July 2000 it was first found in North America in Wisconsin. It rapidly proved to be highly invasive and by 2007 had been found in 20 states. In America the main primary hosts are purging buckthorn (Rhamnus cathartica) and alderleaf buckthorn (Rhamnus alnifolia). Aphis glycines has not been found utilising the European alder buckthorn (Rhamnus frangula) in America despite it being another common invasive common in America, which may explain why it has not yet been found in Europe. On soybean Aphis glycines feeds on the stems and leaf undersides. In Asia it is found in China, Indonesia, Japan, Korea, Malaysia, the Philippines and Thailand. In America Aphis glycines is found primarily in the middle to high latitudes in the midwest U.S., and in Ontario and Quebec provinces in Canada.

 

Other aphids on the same host

Blackman & Eastop list 15 species of aphid as feeding on common buckthorn (=purging buckthorn, Rhamnus cathartica) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 11 as occurring in Britain (Show British list).

Blackman & Eastop list 10 species of aphid as feeding on soybean (Glycine max) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists ? as occurring in Britain: (Show British list).

 

Damage and control

Heavy infestations of soybean aphid can result in yellow and wrinkled leaves, stunted plants and aborted pods. Plants may also be covered with dark sooty mould, growing on the excreted honeydew, which reduces photosynthetic rates. In addition Aphis glycines is known to transmit several plant viruses and has been implicated in increased virus incidence in soybean and snapbean.

Soybean aphids are mainly controlled by the use of insecticides, although efforts have been made to use an integrated pest management approach incorporating use of economic thresholds, host plant resistance and conservation of natural enemies (see Tilman et al., 2011). Classical biological control has also been attempted with the introduction of the braconid parasitoid Binodoxys communis (see parasitoid attacking aphids).

Acknowledgements

We have made provisional identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994) and Blackman & Eastop (2006) supplemented with Blackman (1974), Stroyan (1977), Stroyan (1984), Blackman & Eastop (1984), Heie (1980-1995), Dixon & Thieme (2007) and Blackman (2010). We fully acknowledge these authors 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).

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References

  • Tilman, K.J. et al. (2011). Biology of the Soybean Aphid, Aphis glycines (Hemiptera: Aphididae) in the United States. Journal of Integrated Pest Management 2(2). Full text