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Aphidinae : Macrosiphini : Myzus ascalonicus
 

 

Myzus ascalonicus

Shallot aphid

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

Identification & Distribution:

Myzus ascalonicus apterae are variable in colour from dark green to pale green to dirty yellow (see pictures below). They are noticeably shiny (cf. Myzus cymbalariae, which are not shiny). Their antennal tubercles have their inner faces approximately parallel in dorsal view (cf. Myzus cymbalariae and Myzus persicae, which have the inner faces convergent). Their legs and antennae are usually pale brown, with the ends of the antennae and the tarsi darker. The dorsum is strongly convex (see pictures below) in comparison with related species. The siphunculi are shorter than antennal segment III, distinctly swollen towards the apex, more or less evenly coloured throughout and with only a very small dusky flange (cf. Myzus persicae, which has siphunculi longer than antennal segment III and with a dark tip over the apical 5-10%). The siphunculi have their narrowest part thinner than, or equal in width to, the hind tibia at midlength (cf. Myzus cymbalariae,which has the narrowest part of the stem slightly thicker than the hind tibia at midlength). The cauda is roughly triangular in shape, and short: about one third the length of the siphunculi. The body length of Myzus ascalonicus apterae is 1.1-2.2 mm.

The alate Myzus ascalonicus (see second and fourth image below) has a large central dark patch extending over at least the central areas of abdominal tergites 3-6 or 4-6 (cf. the alate Myzus cymbalariae, which has the dorsal abdominal sclerotization at least partly divided into separate segmental cross bands).

The images below show an apterous and an alate Myzus ascalonicus in alcohol.

The clarified slide mounts below are of adult viviparous female Myzus ascalonicus : wingless, and winged.

Micrographs of clarified mounts by permission of Roger Blackman, copyright AWP all rights reserved.

The shallot aphid does not host alternate in the sense of regular movement from a woody (primary) host species to a herbaceous (secondary) host species. There is no sexual stage in the life cycle and no eggs are produced. Instead Myzus ascalonicus is cold-hardy, and overwinters in glasshouses and sheltered areas, especially on weeds such as chickweeds (Stellaria) and speedwells (Veronica). Numbers may build up even at low temperatures in winter and spring, with alates migrating to other hosts up to mid-June. It is extremely polyphagous, feeding on many wild plant species, as well as crops such as onions, shallots, strawberries, lettuce, brassicas and potatoes and garden ornamentals.

 

Biology & Ecology

Life cycle

Myzus ascalonicus overwinters parthenogenetically on a range of weeds such as chickweeds (Stellaria) and speedwells (Veronica). The picture below shows an apterous adult on Veronica in mid March.

It then disperses to a very wide range of plants over the summer. The female and nymph below are on goldilocks buttercup (Ranunculus auricromus)

 

Other aphids on same host:

Myzus ascalonicus is extremely polyphagous. It has been recorded from plants of numerous genera, in over 20 plant families. It is especially common on members of the onion family (Alliaceae), pink family (Caryophyllaceae), daisy family (Asteraceae), cabbage family (Brassicaceae), lily family (Liliaceae) and rose family (Rosaceae).

  • Myzus ascalonicus has been recorded on 6 Stellaria species (Stellaria graminea, Stellaria holostea, Stellaria media, Stellaria monosperma, Stellaria neglecta, Stellaria nemorum).

    Blackman & Eastop list 19 species of aphid as feeding on chickweed (Stellaria media) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 17 as occurring in Britain (Show British list).

  • Myzus ascalonicus has been recorded on 10 species within the Veronica genus.

    Blackman & Eastop list 11 species of aphid as feeding on speedwell (Veronica beccabunga) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists all 11 as occurring in Britain (Show British list).

  • Myzus ascalonicus has been recorded on 8 species within the Allium genus (Allium ampeloprasum, Allium ascalonicum, Allium cepa, Allium fistulosum, Allium sativum, Allium schoenoprasum, Allium scorodoprasum, Allium ursinum).

    Blackman & Eastop list 9 species of aphid as feeding on onions &/or shallots (Allium cepa =Allium ascalonicum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 8 as occurring in Britain (Show British list).

  • Myzus ascalonicus has been recorded on 3 species within the Fragaria genus (Fragaria × ananassa, Fragaria vesca, Fragaria ×viridis).

    Blackman & Eastop list 28 species of aphid as feeding on garden strawberry (Fragaria × ananassa) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 19 as occurring in Britain (Show British list).

  • Myzus ascalonicus has been recorded on 1 species within the Lactuca genus: Lactuca sativa.

    Blackman & Eastop list 28 species of aphid as feeding on lettuce (Lactuca sativa) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 21 as occurring in Britain (Show British list).

  • Myzus ascalonicus has been recorded on 2 species within the genus Brassica (Brassica napus, Brassica oleracea).

    Blackman & Eastop list 25 species of aphid as feeding on Brassica species worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 21 as occurring in Britain (Show British list).

  • Myzus ascalonicus has been recorded on 1 species within the Solanum genus: Solanum tuberosum.

    Blackman & Eastop list 23 species of aphid as feeding on potato (Solanum tuberosum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists perhaps 21 as occurring in Britain (Show British list).

Acknowledgements

Our particular thanks to Roger Blackman for images of his clarified slide mounts.

Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994) and Blackman & Eastop (2006) supplemented with Blackman (1974), Stroyan (1977), Stroyan (1984), Blackman & Eastop (1984), Heie (1980-1995), Dixon & Thieme (2007) and Blackman (2010). We fully acknowledge these authors 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

 

Identification requests

Alexandra Shaw, March 09, 2014, ID?

Thought of you as I got this plant out of the conservatory earlier today.

Image copyright Alexandra Shaw, all rights reserved.

 

Bob, InfluentialPoints:

  • Thanks for the photo -- they do seem to be doing rather well.

    Sadly, unlike birds, we can rarely ID aphids from a photo - even if it is up-close and personal.

    There are at least 600 aphid species in UK (many of which are fairly plant specific).

    Do you know what plant they were on? Could you send us a live sample in a small plastic box??

    If you have nothing better to do for an afternoon we have some pages on finding and identifying aphids.

    And yes, given the record-breaking mild winter, we expect an awful lot of aphids this year...

Do you really want me to send you some? I'm happy to do so. I've put the plant, a bulb of sorts [probably wild hyacinth], outside from the conservatory so they may have given up in the cold.

Bob, InfluentialPoints:

  • Many thanks for sending us the beasties.

    [Examining the sample, thus far we have only] found "fourth-instar alates" (they have developing wing-buds).

    Given which the rest of the ravening hoard you found has probably matured to adult alates - and flapped-off.

    ...

    As you may have gathered we are trying to raise a few to (wingless) adults so we can identify them.

    One, somewhat mangled bit of [leaf] is in water...

...

Image: InfluentialPoints.

  • Given the siphunculi are clearly swollen and the aphids are brownish green, these are probably Myzus ascalonicus, but only immatures were present - which we were unable to raise through to adults.