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Aphidinae : Macrosiphini : Ericaphis gentneri
 

 

Ericaphis gentneri

Western green hawthorn aphid

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

Identification & Distribution

Fundatrices of Ericaphis gentneri (see picture below) are yellow-green. Their antennae are shorter than the body. They often have one secondary rhinarium on antennal segment III, and the terminal process is about 2.7 times the length of the base of segment VI. The rostrum reaches beyond the second pair of coxae. The siphunculi, which are imbricated with a distinct flange, are about 1.9 times the length of the cauda. The fundatrix cauda is slightly constricted, with 3 pairs of hairs.

Image above copyright Andrew Jensen, under a creative commons licence

Adult apterae of Ericaphis gentneri (not pictured, but resembling the fundatrix above) are broadly spindle-shaped, and coloured light yellow-green to green with no conspicuous markings. The inner faces of the antennal tubercles are smooth and divergent in dorsal view (cf. Myzus ornatus and Myzus persicae, which have the inner faces scabrous and convergent in dorsal view). The antennae are somewhat longer than the body, with minute hairs less than half the basal diameter of the segment in length, and a terminal process that is about 6.9 times the base of antennal segment VI. Segment III occasionally bears one small secondary rhinarium near its base. The rostrum reaches just past the second pair of coxae. The siphunculi have a distinct flange, but no dark tip, and are more or less cylindrical (cf. Utamphorophora crataegi, which has the siphunculi swollen on roughly its distal half). The siphunculi are about 1.7 times the length of the cauda (cf. Aulacorthum solani, which has siphunculi often dark tipped, and more than twice the caudal length). The cauda is slightly constricted, with 3 pairs of hairs (cf. all other Ericaphis species in North America, which have 2 pairs of hairs on the cauda).

Alatae of Ericaphis gentneri (not pictured) have antennae slightly longer than the body, dusky, with minute hairs; there are 18 to 28 secondary rhinaria scattered over the entire length of segment III, not in a straight row, and there is occasionally one rhinarium on segment IV. The abdomen has a large, dorsal, more or less irregularly broken, dark patch, and dark marginal sclerites.

Ericaphis gentneri lives on the leaves and young shoots of woody Rosaceae such as amelanchier (Amelanchier spp.), hawthorns (Crataegus spp.), and whitebeams (Sorbus spp.). It also lives on (non-native) pear (Pyrus communis) and medlar (Mespilus germanica), and was in fact first described by Mason (1947) from specimens on pear. The species is monoecious holocyclic, with oviparae and alate males appearing in September-October. Ericaphis gentneri is restricted to western North America.

 

Other aphids on the same host

Ericaphis gentneri has previously been recorded from 3 hawthorn species (Crataegus douglasii, Crataegus laevigata, Crataegus x lavallei).

Ericaphis gentneri has previously been recorded from 3 species of Amelanchier (Amelanchier florida, Amelanchier laevis, Amelanchier ovalis).

Ericaphis gentneri has been recorded from 1 pear species (Pyrus communis).

Acknowledgements

We are grateful to Andrew Jensen for making his pictures of Ericaphis wakibae available for use under a creative commons licence

Identifications were made by the copyright holder of the pictures. We have used the keys and species accounts of Mason (1947) (as Macrosiphum gentneri) and Pike & Starý (2003) along with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors and those listed in the reference sections 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

  • Mason, P.W. (1947). A new pear aphid (Homoptera, Aphidae). Proceedings of the Entomological Society of Washington 49, (9), 252-254. 40(1), 75-83. Full text

  • Pike, K.S. & Starý, P. (2003). Ericaphis louisae, n. sp. (Hemiptera, Aphididae, Aphidinae: Macrosiphini) on Luetkea pectinata (Pursh) (Rosaceae), and a key to Ericaphis species. Proceedings of the Entomological Society of Washington 105(2), 460-466.