Calaphis betulella (Streaked river birch aphid) identification, images, ecology, control

All adult viviparae of Calaphis betulella are alate (see two pictures below). The alatae are pale yellowish, with one median and two lateral longitudinal black streaks over the head and thorax (cf. Calaphis betulaecolens, which has no black stripes on the dorsum). The antennae are longer than the body. Antennal segments I & II are yellowish with a black streak, and segments III-VI are mostly black, but pale at the base. On the abdominal dorsum there are transverse black bands bordering the anterior and posterior margins of tergites IV and V, and sometimes also on the margins of neighbouring tergites (cf. Calaphis neobetulella, which has a large black quadrate patch on abdominal tergites IV & V). The femora are pale with black stripes, and the tibiae and tarsi are black. The body hairs are short and blunt. The fore wing has the pterostigma and veins narrowly margined with black and smoky at the tips. The radial sector is obsolete, and the media is twice-forked. The siphunculi are dusky and truncate, hardly as long as the tarsi. The cauda is knobbed and bears numerous hairs. The body length of Calaphis betulella adult alate is 2.0-2.5 mm.

Calaphis betulella (streaked river birch aphid) alate vivipara on Betula nigra (river birch) at Kennett Square, Chester County, Pennsylvania, USA on June 1, 2019; Bill Keim

Images above copyright Bill Keim, under a creative commons licence.

Immature Calaphis betulella (not pictured) have dusky spots and long capitate hairs.

Calaphis betulella is monoecious holocyclic on river birch (Betula nigra). It is an agile species, which feeds on the undersides of leaves. It is reportedly common in all parts of Illinois from May to September (Hottes & Frison, 1931). Calaphis betulella is found in the eastern states of the United States, but apparently not in Canada.

Other aphids on the same host

Calaphis betulella occurs on one birch species (Betula nigra).

Blackman & Eastop list 8 species of aphid as feeding on river birch (Betula nigra) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 3 as occurring in Britain (Show British list).

Acknowledgements

We are grateful to Bill Keim for making his images of Calaphis betulella available for use under a creative commons licence.
Identification was made on the Bugguide site by Bill Keim and Natalie Hernandez. We have used the keys and species accounts of Walsh (1863)[1862] and Palmer (1952) 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

Hottes, F.C. & Frison, T.H. (1931). The Plant Lice, or Aphiidae, of Illinois. Illinois Natural History Survey Bulletin 19(3), 123-447. Full text
Palmer, M.A. (1952). Aphids of the Rocky Mountain Region: including primarily Colorado and Utah, but also bordering area composed of southern Wyoming, southeastern Idaho and northern New Mexico. Thomas Say Foundation, Denver. Full text
Walsh, B.D. (1863)[1862] On the genera of Aphidae found in the United States. Proceedings of the Entomological Society of Philadelphia 1, 294-310 (p 301). Full text

Calaphis betulella

Streaked river birch aphid

Identification & Distribution

Other aphids on the same host

Acknowledgements

Useful weblinks

References