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Eriosomatinae : Pemphigini : Prociphilus americanus : spp. list
 

 

Prociphilus americanus

Balsam-fir root aphid

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

Identification & Distribution

Fundatrices of Prociphilus americanus on the new growth of ash in spring are dark brown to black, and globose. All offspring develop to emigrant alatae (see pictures below) which are very dark green to black with a dusky, head and dark antennae. Oval mesothoracic wax plates and large lateral abdominal wax plates produce long flocculent wax on the body, but the head of the alate is without (rarely with) wax plates. Antennal segment III is less than 5 times segment II (cf. Prociphilus bumeliae, which has segment III more than 5 times segment II). Secondary rhinaria on antennae are distributed 8-23 on segment III, 0-9 on IV and 0-2 on V. (cf. Prociphilus oriens, in which the alate has 5-11 secondary rhinaria on segment V). The apical rostral segment (RIV+V) is 0.56-0.72 times the second hind tarsal segment (HTII) (cf. Procophilus fraxini, which has RIV+V 0.50-0.55 times HTII). Number of hairs on tarsal segment I is usually 2-2-2 (fore-mid-hind). Wings are pale, not as dusky as in the sexuparae. The genital plate has about 60-80 hairs, the major portion of which are on the caudal half. The cauda bears 7-14 hairs. Body length of Prociphilus americanus alatae is 2.8-4.8 mm.

First image copyright Gary Chang; second image copyright Steve Wells,
both under a creative common licence.

The body of the apterous Prociphilus americanus vivipara is oval and pale, and in life covered with flocculent wax (see first picture below for immatures and second picture below for colony). The head and thorax have rounded wax glands, and the abdomen has marginal wax glands. The antennae have four to five segments, and are quite short; they are 0.36-0.56 times body length, with a short terminal process, 0.15-0.38 times the base of the last antennal segment. They are without secondary rhinaria. The rostrum is long, distinctly extending beyond the metacoxae. The apical rostral segment is 2.57-3.48 times its width, with 12-20 accessory hairs. The number of hairs on tarsal segment I is 3-2-2 (fore, mid, hind). Hairs are easily visible on the body and appendages. The dorsum is smooth. The anal plate is conspicuously protruding. The cauda has 15-32 hairs. Body length of adult Prociphilus americanus apterae is 1.39-2.34mm.

First image copyright James Bailey; second image Eric R. Day,
Virginia Polytechnic Institute and State University, Bugwood.org, both under a creative common licence.

Prociphilus americanus host alternates from ash (Fraxinus) or lilac (Syringa) to the roots of fir (Abies). Fundatrices on ash form early spring colonies on curled terminal leaves of new growth or on twigs, with populations also developing on suckers, and at base of the trunk, or even underground. Migrant alatae maturing from late April to early June found wax-covered colonies on Abies roots. Sexuparae return to produce dwarf sexual morphs on trunk of Fraxinus in late August-October. Patch (1909) described the sexual morphs (as Prociphilus venafuscus), and recorded that they were also deposited by sexuparae in large numbers on lilac (Syringa) which seems likely to be an alternative primary host (for Prociphilus sexuparae on Syringa see here). Anholocyclic overwintering may also occur on Abies roots. Prociphilus americanus is widely distributed in North America.

 

Other aphids on the same host

Primary hosts

Prociphilus americanus has been recorded on 5 Fraxinus species (Fraxinus americana, Fraxinus dipetala, Fraxinus excelsior, Fraxinus latifolia, Fraxinus pennsylvanica).

Prociphilus americanus has also been recorded on 1 Syringa species (Syringa vulgaris).

Secondary hosts

Prociphilus americanus has been recorded on the roots of 5 Abies species (Abies alba, Abies balsamea, Abies grandis, Abies procera).

Acknowledgements

We are grateful to Gary Chang, Steve Wells, James Bailey & Eric Day for putting their images under a creative commons licence.

We have used the species accounts given by Patch (1909) (as Pemphigus venafuscus), Essig (1911) (as Pemphigus fraxini-dipetalae), Doncaster (1961), Smith (1969), and Pike et al (2012), together 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 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

  • Doncaster, J.P. (1961). Francis Walker's Aphids. British Museum (Natural History), London. 165 pp. (p. 24) Full text

  • Essig, E.O. (1911). Aphididae of southern California. Pomona College Journal of Entomology 3(3), 523-557 (p. 553).

  • Patch, E.M. (1909). Pemphigus venafuscus n. sp. Entomological News 20, 319-322. Full text

  • Pike, K.S. et al. (2012). Eriosomatine aphids (Hemiptera: Aphididae: Eriosomatinae) associated with moss and roots of conifer and willow in forests of the Pacific Northwest of North America. The Canadian Entomologist 144(4), 555-576. (p. 569) Abstract

  • Smith, C.F. (1969). Pemphiginae associated with roots of conifers in North America (Homoptera: Aphididae). Annals of the Entomological Society of America 62(5), 1128-1152. (p. 1136) Abstract