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Aphidinae : Macrosiphini : Pleotrichophorus chrysanthemi
 

 

Pleotrichophorus chrysanthemi

Bristly chrysanthemum aphid

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

Identification & Distribution

Adult apterae of Pleotrichophorus chrysanthemi (aphid top-right in second picture below, the others are immature) are pale green to yellowish, with longitudinal bands of light wax dusting which give the appearance of darker green median and pleural lines. The apices of their antennae, tibiae and siphunculi are dusky, and the tarsi are dark. The antennae are longer than their body, with a very long terminal process, 5-9 times the length of the base of antennal segment VI (cf. Coloradoa rufomaculata, which has antennae shorter than the body). The head has antennal tubercles, and a moderately-developed median frontal tubercle, all bearing capitate hairs. The rostrum reaches to just past the second coxae, and the apical segment is narrow and acuminate (=tapers to a point). The abdomen has a membranous dorsum bearing many strongly capitate hairs (cf. Coloradoa rufomaculata, which has fan-shaped dorsal hairs). The siphunculi are pale with a dusky apex, very thin, about as long as antennal segment IV, and with no polygonal reticulation (cf. Macrosiphiniella sanborni, which has a zone of polygonal reticulation on the siphunculi). The cauda is pale, rather long and thick, with 3 hairs. The anal plate is slightly darkened, rounded, with a few long hairs. The body length of adult apterae is 1.8-2.4 mm. Immatures (most aphids in pictures below) are very similar to the adult, but have a triangular rather than elongate cauda.

Note: The primary distinction between Pleotrichophorus chrysanthemi and Pleotrichophorus glandulosus is their host preference, but there are a few morphological differences. Most Pleotrichophorus chrysanthemi apterae (feeding on Dendranthema) have 7-8 hairs on their abdominal tergite, whereas most Pleotrichophorus glandulosus (feeding on Artemisia vulgaris) have 8-13. Most Pleotrichophorus chrysanthemi alatae have no secondary rhinaria on antennal segment IV, whereas most Pleotrichophorus glandulosus alatae have 3 or more.

Images above by permission, copyright Sunil Joshi & Poorani, J. Aphids of Karnataka (accessed 12/2/20).

The alate viviparous female (not pictured) is pale yellowish to pale green, with a brown head and thorax, and paired dusky dorsal intersegmental markings. The antennae have 10-18 secondary rhinaria in a line along the whole length of segment III.

Image above by permission, copyright Sunil Joshi & Poorani, J. Aphids of Karnataka (accessed 12/2/20).

Pleotrichophorus chrysanthemi are monoecious on the undersides of leaves of florists(tm) chrysanthemums (Dendranthema). They are entirely anholocyclic, and no sexual forms have been found. The 'species' is thought to have arisen quite recently as a clone of Pleotrichophorus glandulosus able to feed on Dendranthema. Pleotrichophorus chrysanthemi is found in most parts of the world where chrysanthemums are grown.

 

Other aphids on the same host

Blackman & Eastop list 30 species of aphid as feeding on "florists' chrysanthemums" (Chrysanthemum indicum = Dendranthema indicum & Chrysanthemum morifolium =Dendranthema morifolium) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 24 as occurring in Britain (Show British list).

Acknowledgements

We are very grateful to Sunil Joshi & J. Poorani, Aphids of Karnataka for permission to reproduce their images of the live aphids.

We have used the keys and species accounts of Theobald (1929) (as Capitophorus chrysanthemi) 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

  • Theobald, F.V. (1929). The plant lice or Aphididae of Great Britain. Vol 3. Headley Bros., London (p 331).