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Cinara fresai

American juniper aphid, Large juniper aphid

On this page: Identification & Distribution Other aphids on the same host

Identification & Distribution

Adult apterae of Cinara fresai (see pictures below) are pinkish-grey to dark brownish-grey or greenish-grey. They are dusted with white wax down the midline and laterally, quite thickly on the thoracic segments but less heavily on the abdominal segments. They have paired black patches on thoracic and anterior abdominal tergites diverging in an inverted V. The body and appendages are clothed with long pale hairs. The base of antennal segment VI has 7-12 hairs not restricted to the basal half (cf. Cinara cupressi which has 4-7 hairs restricted to the basal half ). Rostral segment IV has 5-7 accessory hairs (see micrograph below) (cf. Cinara cupressi which has 2-4 hairs on RIV). The distal parts of the hind femora are dusky or dark (cf. Cinara tujafilina which has hind femora pale). The bases and apices of the hind tibiae are dusky or dark but with a paler area in between (cf. Cinara juniperi which has the hind tibiae uniformly dark). The body length of adult Cinara fresai apterae is 2.2-4.2 mm.

The alate Cinara fresai (not pictured) is unusual in having the radial sector not reaching the apex of the forewing. The abdominal pattern is reduced in comparison to the aptera.

The micrographs below show an adult aptera of Cinara fresai, dorsal and ventral, and rostral segments RIV and RV, with 5-6 accessory hairs on RIV.

N.B. Based on counts of the hairs on the base of antennal segment VI, and on rostral segment IV, we are reasonably confident that these aphids are Cinara fresai and not the (presumably more common) Cinara cupressi. However, we do not prepare clarified slide mounts of all the aphids we find, and it can be difficult to make accurate counts of hairs on specimens in alcohol. Hence we cannot be absolutely certain of the identification of the specimens shown here. They were living in small loosely ant-attended colonies on an ornamental juniper, tentatively identified as Juniperus x pfitzeriana, a cross between two preferred hosts of Cinara fresai (Juniperus chinensis and Juniperus sabina).

Cinara fresai feeds on the needles and adjacent woody shoots and branches of various Cupressaceae, especially junipers (Juniperus chinensis, Juniperus sabina, Juniperus squamata and Juniperus virginiana and their cultivated varieties), but not apparently in Europe on the native common juniper (Juniperus communis). Cinara fresai has also been reported on some Cupressus species. Reproduction is entirely parthenogenetic. No sexual forms have ever been found. It is sometimes attended by ants. As with Cinara cupressi large infestations can lead to the development of sooty mould and blackening of shoots, and can cause diebacks of shoots and death of trees. Cinara fresai presumably got its common name (American juniper aphid) from its presence on Juniperus virginiana, but its other preferred hosts suggest it is may be native to the Far East rather than America, and has been spread worldwide by the plant trade. It has been recorded from Japan, Korea, Australia, New Zealand, England & Wales, Poland, Spain, Israel, USA, Central and South America.

 

Other aphids on the same host

Cinara fresai has been recorded from 11 Juniperus species and 8 Cupressus species.

Blackman & Eastop list 28 species of aphid as feeding on juniper (Juniperus spp) worldwide, and provide formal identification keys.

Of those aphid species, Baker (2015) lists 7 as occurring in Britain: Cinara fresai, Cinara juniperi, Cinara smolandiae, Cinara tujafilina, Gootiella tremulae, Illinoia morrisoni and Macrosiphum euphorbiae.

Blackman & Eastop list 9 species of aphid as feeding on cypresses (Cupressus species) worldwide, and provide formal identification keys.

Of those aphid species, Baker (2015) lists 5 as occurring in Britain: Aphis craccivora, Cinara cupressi, Cinara fresai, Cinara tujafilina and Illinoia morrisoni.

Acknowledgements

We especially thank the UK Forestry Commission, Bedgebury Pinetum, for their kind assistance, and permission to sample.

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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