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Aphididae : Calaphidinae : Panaphidini : Chromaphis


Genus Chromaphis

Small walnut aphids

On this page: Chromaphis juglandicola

Genus Chromaphis [Panaphidini]

Chromaphis aphids are small, pale and yellow with all viviparae winged and living on walnut (Juglans species).

This genus has just 2 species, both Palaearctic. Chromaphis aphids have also been recorded on Aleurites moluccana (the candlenut, or Indian walnut, a flowering tree in the spurge family) which presumably acts as a reserve host, rather than a true secondary host.


Chromaphis juglandicola (Small walnut aphid) Europe, Asia, North America

Adult viviparae of Chromaphis juglandicola are all winged. Fourth instar nymphs (first picture below) are yellow or 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 body length. 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 Chromaphis juglandicola 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. Chromaphis juglandicola is found in Europe, Central Asia, India, Pakistan, China and North America.



Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made 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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