Biology Reference
In-Depth Information
100
101
100
Colony of mealy plum aphid (
Hyalopterus pruni
) on
Prunus
.
101
Colony of
Illinoia azaleae
on
Rhododendron
.
102
LIFE HISTORY
Aphids breed parthenogenetically throughout the year,
producing winged forms in both spring and summer.
Infestations are most common in greenhouses and hot-
houses but also persist outdoors in mild districts.
DAMAGE
Infested fern fronds are distorted, and may turn black
and die.
Illinoia azaleae
(Mason) (
101
)
A common pest of container-grown azaleas
(
Rhododendron
), having been introduced into Europe
from North America on infested plants. Heavy
infestations reduce the vigour of host plants and cause
defoliation. Attacks may also occur on open-bedded
bushes growing in parks and gardens. Reproduction is
typically parthenogenetic and viviparous, and is
continuous so long as conditions remain favourable.
Adults are medium-sized, spindle-shaped, deep green
and shiny, with long, mainly pale, slightly swollen
siphunculi.
102
Colony of
Illinoia lambersi
on
Rhododendron
.
Illinoia liriodendri
(Monell)
Tulip-tree aphid
This North American species, which is associated with
tulip tree (
Liriodendron tulipifera
), was found in France
in 1998, and has since been reported elsewhere in
Europe, including Britain (southern England and
Wales), Germany, Italy and Slovenia. The aphid has also
appeared in Japan. Heavy infestations occur on the
leaves, and the aphids excrete considerable quantities of
honeydew. Apterae (1.8-2.7 mm long) are mainly light
green, lightly dusted with white wax, with mainly black
but basally pale siphunculi and a yellow cauda.
Illinoia lambersi
(MacGillivray) (
102
)
A North American species, now well established on
azalea (
Rhododendron
) in parts of Europe, including
Denmark, England and the Netherlands. Colonies
develop mainly on the new shoots and flower buds. The
aphids are similar in appearance to
Illinoia azaleae
, but
are larger and either green, pink or yellow, the various
colour forms often occurring together.
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