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Genus Chromaphis

Small walnut aphids

Species Overview: Genus Chromaphis  Chromaphis juglandicola 

 

Chromaphis juglandicola (Small walnut aphid)

Adult viviparae are all winged. Fourth instar nymphs (first picture below) are yellowish white, and (in autumn) have paired brown spots on abdominal tergites 4 and 5. The alates (second picture below) are yellowish-white with pale brown thoracic lobes and paired brown spots on abdominal tergites 4 and 5. The antennae have dark brown tips and are about half the length of the body; the terminal process is 0.2 times the length of the base of the last antennal segment. The siphunculi are conical and smooth. The body length of alates is 1.2-2.3 mm.

 

The small walnut aphid lives scattered on the undersides of leaves of walnut (Juglans regia). Oviparae and males occur in May-June in India, and in autumn in Europe and the USA. It is found in Europe, Central Asia, India, Pakistan, China and North America.

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).

Useful weblinks 

References

  •  Dixon, A.F.G. & Thieme, T. (2007). Aphids on deciduous trees. Naturalist's Handbooks 29. Richmond

  •  Stroyan, H.L.G. (1977). Homoptera: Aphidoidea (Part) - Chaitophoridae and Callaphidae. Handbooks for the identification of British insects. 2 (4a) Royal Entomological Society of London. Full text