Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 43

Aphis viburni Scopoli ( 66 )
Viburnum aphid
A common pest of wild and ornamental species of
Viburnum , including guelder-rose ( V. opulus ). Widely
distributed in Europe.

unlikely to survive the winter outdoors in northern
Europe. Other subspecies overwinter as eggs on outdoor
hosts, e.g. alder buckthorn ( Frangula alnus ); they
inhabit various herbaceous hosts during the summer,
including ornamentals such as Hypericum .

DAMAGE
Attacked leaves turn yellow and may wilt and die. The
appearance of ornamentals is also spoilt by the
accumulation of honeydew, development of sooty
moulds and presence of cast aphid skins.

DESCRIPTION
Apterous female: 1.8-3.0 mm long; dark greenish
black to brownish black; siphunculi relatively short.
Nymph: brownish, liberally coated with white wax.

LIFE HISTORY
This species overwinters in the egg stage on the shoots
and branches of host plants. The eggs hatch in the early
spring, usually from April onwards. Aphids then feed on
the underside of leaves on the young shoots. The sexual
phase in the lifecycle includes a generation of wingless
males. Colonies, which are ant-attended, tend to appear
brownish in colour, and often extend onto the
inflorescences. They reach their maximum development
relatively early in the season and then decline as winter
eggs are laid; the aphids have usually disappeared by
mid-summer. Aphis fabae also infests guelder-rose, but
such colonies are longer-lasting and appear black rather
than brown.

64

DAMAGE
Spring infestations curl the leaves of new shoots, the
deformed foliage remaining on the bushes long after the
aphids have disappeared. The presence of damaged
shoots spoils the appearance of ornamental shrubs;
Viburnum carlesii

is most susceptible and may be

severely disfigured. 64 Colony of melon & cotton aphid ( Aphis gossypii ) on

Hypericum .

66

65

65 Melon & cotton aphid ( Aphis gossypii ) damage to foliage
of Chrysanthemum .

66 Viburnum aphid ( Aphis viburni ) damage to shoots of
Viburnum carlesii .