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Genus Corylobium

Hazel aphids

On this page: Genus Corylobium  Corylobium avellanae 

Genus Corylobium [Macrosiphini]

Green, sometimes reddish, medium sized spindle-shaped aphids, the adult viviparae of which may be winged or wingless. The antennae are longer than the body. The median and antennal tubercles are well developed, and the inner margins of the antennal tubercles diverge. The body has numerous capitate hairs arising from tubercles on the body - just visible in this image. The siphunculi are long and thin and the cauda is very short and triangular.

There is only 1 species in this genus which lives on hazel (Corylaceae). It is widely distributed in Europe and has been introduced to North America. It retains a sexual stage in its life cycle, and is not attended by ants.


Corylobium avellanae (Large hazel aphid)

Apterae are yellowish-green often mottled with red spots. The antennae are pale with dark tips to the segments and black apices. The dorsum is granulate with numerous small cuticular structures and 6-8 low conical tubercles per segment, each with one or two long thick capitate hairs. The siphunculi are long, thin and tapering, 4.2-5.5 times the length of the cauda. The body length of apterae is 1.7-2.9 mm.


The large hazel aphid does not host alternate but spends its entire life cycle on hazel (Corylus avellana). Sexual forms occur in autumn and overwintering eggs are laid on hazel. It feeds on the fast growing shoots, rarely on the leaves which are utilized by another species - Myzocallis coryli. It is distributed over most of Europe east to Ukraine and Russia.

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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 


  •  Heie, O.E. (1980-1995). The Aphidoidea, Hemiptera, of Fennoscandia and Denmark. (Fauna Entomologica Scandinavica) E.J. Brill, London