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Identification & Distribution:
Macrosiphum euphorbiae apterae are either green with a darker green longitudinal stripe or red (see pictures below), and often rather shiny. Their eyes are reddish, and the antennae are darker towards their tips. Their femora are brownish and rather pale with the apices not dark or only slightly so. The siphunculi are pale sometimes with the tips darker, but not as dark as the tips of the tibiae. They are reticulated on the apical 13-20% and are 1.7-2.2 times the length of the cauda. The cauda is rather pointed and not constricted. The body length of Macrosiphum euphorbiae apterae is 2.0-4.0 mm.
The alate (see first picture below) has pale greenish to yellow-brown thoracic lobes, with only the antennae and siphunculi noticeably darker than in the apterae. The second picture below shows a small colony of Macrosiphum euphorbiae on rose.
The clarified slide mounts below are of adult viviparous female Macrosiphum euphorbiae : wingless, and winged.
Micrographs of clarified mounts  by permission of Roger Blackman, copyright AWP all rights reserved.
The potato aphid is a common and highly polyphagous species. It is often a pest on various crops such as potato (Solanum tuberosum), lettuce (Lactuca sativa) and beets (Beta vulgaris) as well as on numerous garden ornamentals. Macrosiphum euphorbiae is a vector of about one hundred plant viruses. The species originates from the north-eastern USA where it produces sexual forms and host alternates with rose (Rosa) as its primary host. Elsewhere it usually overwinters as viviparae. Aphid numbers increase rapidly from early spring, and alates spread infestations to other plants. It is an especial problem in unheated greenhouses. Macrosiphum euphorbiae was introduced to Europe about 1917 and is now cosmopolitan.
Other aphids on same host:
Primary host
- Macrosiphum euphorbiae is only known to use Rosa species a primary host (specifically, for sexual reproduction) in north-eastern USA. In addition (there and elsewhere) Macrosiphum euphorbiae reproduces parthenogenetically on Rosa species, including cultivated roses. For an aphid species list see our rose aphids page.
Secondary hosts
- Blackman & Eastop list 23 species of aphid as feeding on potato (Solanum tuberosum) worldwide, and provide formal identification keys.
Of those aphid species, Baker (2015) lists perhaps 21 as occurring in Britain:
Acyrthosiphon malvae,
Aphis craccivora,
Aphis fabae,
Aphis frangulae,
Aphis frangulae ssp. beccabungae,
Aphis gossypii,
Aphis nasturtii,
Aphis solanella,
Aphis spiraecola,
Aulacorthum solani,
Brachycaudus helichrysi,
Macrosiphum euphorbiae,
Myzus antirrhinii,
Myzus ascalonicus,
Myzus ornatus,
Myzus persicae,
Neomyzus circumflexus,
Pemphigus sp.,
Rhopalosiphoninus latysiphon,
Rhopalosiphum rufiabdominale
and
Smynthurodes betae.
- Blackman & Eastop list 28 species of aphid as feeding on lettuce (Lactuca sativa) worldwide, and provide formal identification keys.
Of those aphid species, Baker (2015) lists 21 as occurring in Britain:
Acyrthosiphon lactucae,
Aphis fabae,
Aphis gossypii,
Aphis spiraecola,
Aulacorthum solani,
Brachycaudus helichrysi,
Hyperomyzus lactucae,
Macrosiphum euphorbiae,
Myzus ascalonicus,
Myzus cymbalariae,
Myzus ornatus,
Myzus persicae,
Nasonovia ribisnigri,
Neomyzus circumflexus,
Pemphigus bursarius,
Protaphis terricola,
Trama caudata,
Trama troglodytes,
Uroleucon cichorii,
Uroleucon picridis
and
Uroleucon sonchi.
- Blackman & Eastop list 22 species of aphid as feeding on beets (Beta vulgaris) worldwide, and provide formal identification keys.
Of those aphid species, Baker (2015) lists 18 as occurring in Britain:
Aphis craccivora,
Aphis fabae,
Aphis gossypii,
Aphis nasturtii,
Aphis sambuci,
Aphis solanella,
Aulacorthum solani,
Brachycaudus helichrysi,
Brevicoryne brassicae,
Hayhurstia atriplicis,
Macrosiphum euphorbiae,
Macrosiphum stellariae,
Myzus ascalonicus,
Myzus persicae,
Pemphigus fuscicornis,
Rhopalosiphoninus latysiphon,
Rhopalosiphoninus staphyleae ssp. tulipaellus
and
Smynthurodes betae.
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Identification requests
Sally Luker, 22 May 2014, RE: Aphid records
Just sorting out pics, and have happened upon these little lovelies from November, which I've been unable to which I've been unable to put a name. They were on cotton growing in the Mediterranean Biome at the Eden Project.
Are you able to help?!
Image(s) copyright Sally Luker, all rights reserved.
Bob, InfluentialPoints: -
Had a look at your aphids on cotton.
The adult appears to have been killed by an Entomophthora fungus giving it the bright orange/red colour.
This aphid fits all the requirements of Macrosiphum euphorbiae: antennal tubercules high smooth and divergent, femora rather pale with the apices not dark, siph pale with the tips darker and the cauda rather pointed and not constricted. (E.g. see our Macrosiphum page ) It is recorded on Gossypium herbaceum by Blackman.
I was actually wondering about fungification but the aphid didn't seem in too bad a shape, so I casually dismissed that, which left me unnecessarily pondering - that'll teach me!
Alan Outen, 03 June 2014, Re: Aphid hunting
I came across a dead ringer (I think!) for a species that I found the other day, 31 May 2014, on Pear (Pyrus communis cv) at Langford Garden Centre, Beds. The 'match-images' purport to be Macrosiphon euphorbiae, though they look rather different to your own and other images of this and the other day I had rejected this as a possibility! They were in fact from the 'Azoresbioportal' website! I normally try to avoid getting too involved with on-line images of many insects as so many are clearly wrongly identified (as also many of fungi!). Any suggestions?
Image(s) copyright Alan Outen, all rights reserved.
Bob, InfluentialPoints: -
Looks like Macrosiphum euphorbiae - first two are IV instar future alates.
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InfluentialPoints.com
Other aphids on the same host