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Genus Phylloxera

Phylloxera aphids

On this page: Genus Phylloxera Phylloxera glabra

Phylloxera [Phylloxeridae]

Phylloxera are small pear-shaped aphids (using 'aphids' in the loose sense, phylloxerids are not 'true' aphids). Both the sexual and parthenogenetic females are oviparous. The wings are held flat over the abdomen at rest. The ovipositor is vestigial or absent.

Phylloxera feed on plants in the walnut (Juglandaceae) and oak/chestnut (Fagaceae) families.

 

Phylloxera glabra (Oak leaf phylloxera)

Phylloxera glabra fundatrices feeding on oak leaves in spring causes the leaf edges to curl inwards. Feeding by later generations causes necrotic spots on the leaves (see first picture below). The yellowish orange adult apterae feed on the undersides of the leaves (see second picture below of adult with eggs). The dorsal processes of the aptera are undeveloped, and the tergum (=thickened dorsal plate) is nearly smooth (cf. Pylloxera quercus sp. group, including Phylloxera coccinea, which have club-shaped dorsal processes on the thorax). The primary rhinarium on the third antennal segment is subapical (=below or near the apex) with the terminal process developed. Abdominal tergites 2-5 have spiracles. The Phylloxera glabra adult body length is 0.7-0.85 mm.

The oak leaf phylloxera lives without host alternation on oak leaves (mainly Quercus robur). Female Phylloxera glabra surround themselves with concentric circles of their eggs (see picture above). After hatching, their nymphs wander off leaving gaps in the circle, or if disturbed, the adult female may leave. Phylloxera glabra is found in Europe, and has been introduced to New Zealand.

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Acknowledgements

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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References

  • Blackman, R.L. & Eastop, V.F. (2006). Aphids on the world's herbaceous plants and shrubs. Vols 1 and 2. John Wiley & Sons.