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Potato aphidOn this page: Identification & Distribution Other aphids on the same host
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 noticeably red, and the antennae are darker towards their tips. The fused apical rostral segment (RIV+V) is 0.83-1.02 times longer than the second hind tarsal segment (HTII) (cf. Macrosiphum tinctum for which RIV+V is 0.98-1.11 times longer than HTII and cf. Macrosiphum funestum for which RIV+V is 1.2-1.5 times longer than HTII). Their femora are brownish and rather pale with the apices not dark or only slightly so (cf. Macrosiphum hellebori, Macrosiphum gei, Macrosiphum cholodkovskyi and Macrosiphum euphorbiellum which all have dark apices to the femora). The siphunculi are pale sometimes with the tips darker, but not as dark as the tips of the tibiae (cf. Macrosiphum rosae which has the siphunculi entirely black). The siphunculi 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 third picture above) has pale greenish to yellow-brown thoracic lobes, with only the antennae and siphunculi noticeably darker than in the apterae.
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:
Macrosiphum euphorbiae is only known to use Rosa species as 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.
Blackman & Eastop list 61 species of aphid as feeding on Rosa spp. (both cultivated and wild) worldwide, and provide formal identification keys. (Show World list). Of those aphid species, Baker (2015) lists 24 as occurring in Britain (Show British list).
Blackman & Eastop (1984) list around 30 species of aphid as feeding on cultivated 'roses' worldwide, and provide formal identification keys. (Show World list). Of those aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).