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Identification & Distribution:

Apterae of Cinara confinis are dark brown or greenish-black, with a double row of blackish slightly shining speckles and small flecks of fine wax in transverse rows. The head and thoracic plates are dark brown. The antennae are pale yellowish-grey with a darkening of each segment distally. Cinara confinis tarsi are black. The tibia and femora either have dark brown annulations or are mainly black. The siphuncular cones are dark and prominent. The body length is 3.8-7.8 mm

 

The length of the sclerotized part of the stylet groove is greater than 1.8 mm. The length of the fifth antennal segment, including the terminal process, is clearly longer than the fourth antennal segment.

The clarified slide mounts below are of adult viviparous female Cinara confinis : wingless, and winged.

 

Micrographs of clarified mounted  aptera & alate courtesy Favret, C. & G.L. Miller, AphID.  Identification Technology Program, CPHST, PPQ, APHIS, USDA; Fort Collins, CO.

Cinara confinis feeds on the stems and twigs (rarely on the roots) of various fir (Abies) and cedar (Cedrus) species. It has a holarctic distribution and is recorded from Europe, much of Asia, North America (formerly known as Cinara grossa) and Argentina. Carter & Maslen (1982)  describe it as of sporadic occurrence in Britain occurring in northern Scotland, west of Ireland and southern England.

 

Biology & Ecology:

Struble et al. (1976)  describe the biology of Cinara confinis (under the name Cinara abieticola) in Maine, USA. Fundatrices were first found in May at the bases of buds. Resultant colonies were generally located on the trunk just below the first whorl of branches, as shown in the picture below for a colony in Sussex, UK.

Colonies disperse rapidly if disturbed. Apterous females tend to drop off but nymphs move rapidly up or down the stem and on to the branches The picture below shows a dispersing nymph moving away from a disturbed colony.

 

In Maine, colonies on fir trunks declined by mid June as aphids moved to root collar and roots. Winged males, oviparae and eggs can be found in October.

Binazzi & Scheurer (2009)  report that Cinara confinis is optionally dependent on ant attendance. This species sometimes occurs in special earth galleries constructed by ants on the bark of fir trees (Wood-Baker, C., 1964 ). The only colony we have found was strongly attended by southern wood ants (Formica rufa).

 

Despite the attendance of wood ants, several of the colony had been parasitized. The resultant aphid mummies were blackish and are shown below left. The adult parasitoid is shown below right.

 

On the basis of the extraordinary number of antennal segments (Baker, pers. comm.), this parasitoid is almost certainly Pauesia grossa. This species is a parasitoid specific to Cinara confinis, but it has not been previously recorded in UK. Few predators have been observed around Cinara confinis colonies, although Struble et al. (1976)  reported larvae of Metasyrphus medius in June.

 

Damage and control

This aphid can occur in enormous numbers on large fir and cedar trees grown for their amenity value in urban areas. With large infestations the tendency of the aphids to wander about a lot means they can cause a public nuisance which is accentuated by the honeydew deposits, sooty moulds and abundant wasps.

The image above is of an Abies amabilis (Pacific silver fir) found infested with Cinara confinis at Bedgebury Pinetum, UK.

Acknowledgements

We are grateful to the UK Forestry Commission, Bedgebury Pinetum,  for their kind assistance.

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

  •  Binazzi, A. & Scheurer, S. (2009). Atlas of the honeydew producing conifer aphids of Europe. Aracne. 132 pp. Introduction 

  •  Carter, C.R. & Maslen, N.R. (1982). Conifer Lachnids. Forestry Commission Bulletin No. 58, 75pp.

  •  Strubble, D.B. et al. (1976). Notes on the biology of Cinara abieticola (Chlodkovsky) in Maine and descriptions of sexuales (Homoptera: Aphididae). Entomological News 87, 280-284.Abstract 

  •  Wood-Baker, C. (1964). Records of sixty-six European and British aphids. (Hem., Aphididae). Entomologist's Monthly Magazine 100, 43-48.