Biology Reference
In-Depth Information
Family APHIDIDAE (aphids)
LIFE HISTORY
Adults and eggs overwinter on perennial plants such as
clover ( Trifolium ), lucerne ( Medicago sativa ), sainfoin
( Onobrychis vicifolia ) and trefoil ( Lotus ). Colonies
develop on these plants in the spring, winged forms
migrating to peas and beans from May onwards.
Immigrants invade the growing points, and infestations
then build up on the shoots and developing pods. The
aphids, which readily drop to the ground if disturbed,
often form significant infestations in June and July, and
colonies usually persist on such hosts into the autumn.
A major group of phytophagous winged (alate) and
wingless (apterous) insects in which alternation of
generations between winter and summer hosts is
commonplace and lifecycles of individual species are
often complex. Many species show an alternation of
generations, having a primary (winter) host upon which
asexual and sexual reproduction occurs and eggs are
laid, and a secondary (summer) host where
development is entirely parthenogenetic and viviparous.
Migration between these alternate hosts is usually
achieved following the production of winged forms.
Here, aphids are arranged alphabetically under the
following subfamilies: Aphidinae (p. 49 et seq .),
Callaphidinae, Drepanosiphinae and Phyllaphidinae
(p. 72 et seq .), Chaitophorinae (p. 78 et seq .),
Eriosomatinae (p. 80 et seq .), Hormaphidinae (p. 87),
Lachninae (p. 87 et seq .), Mindarinae (p. 93 et seq .),
Pterocommatinae (p. 93 et seq .) and Thelaxinae (p. 94
et seq .). These subfamilies were granted full family
status in older classification schemes.
DAMAGE
Most damage is caused to the growing points during
June and July, affected leaves becoming distorted and
turning yellow. Pea enation mosaic virus, pea leaf roll
virus and pea mosaic virus are introduced and spread by
this insect.
Acyrthosiphon malvae (Mosley)
syn. A. pelargonii (Kaltenbach)
Pelargonium aphid
Infestations of this medium-sized, light green or
yellowish aphid sometimes occur on greenhouse-grown
Pelargonium , often in company with other species such
as Aulacorthum circumflexum (p. 56). The aphid also
infests other ornamentals, including Cineraria , but is
rarely important. Apterae are 2.5-3.0 mm long, with
very long antennae, divergent antennal tubercles, and
elongate, tapered siphunculi and cauda; unlike species
of Macrosiphoniella
Subfamily APHIDINAE
Aphids with terminal process of antennae elongate;
siphunculi typically cylindrical, tapered or swollen,
with or without an apical flange; cauda often triangular,
tongue-shaped or finger-shaped.
Acyrthosiphon pisum (Harris) ( 61 )
syn. A. onobrychis (Boyer de Fonscolombe);
A. pisi (Kaltenbach)
Pea aphid
A generally common pest of certain cultivated legumes
(Fabaceae), including sweet pea ( Lathyrus odoratus ).
Virtually cosmopolitan. Widespread in Europe. The
subspecies Acyrthosiphon pisum spartii occurs on wild
and cultivated broom ( Cytisus ).
and Macrosiphum
(q.v.) the
siphunculi are not reticulated at the apex.
61
DESCRIPTION
Apterous female: 2.5-4.4 mm long; elongate, light
green to yellowish or pinkish, with long antennae, legs
and cauda, and very long siphunculi. Alate: 2.3-4.3 mm
long; similar to aptera. Nymph: similar to adult but
lightly dusted with wax.
61 Colony of Acyrthosiphon pisum spartii on Cytisus .
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