Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 64

Subfamilies CALLAPHIDINAE,
DREPANOSIPHINAE &
PHYLLAPHIDINAE

adults, also occur on the underside of the leaves, either
singly or in small groups. There is a succession of
generations throughout the spring and summer months
but dense colonies develop only if conditions are
particularly favourable. Aphids with terminal process of the antennae of

variable length, siphunculi usually stumpy or broadly
conical but sometimes pore-like or long and swollen,
anal plate often divided into two lobes, and cauda knob-
like or rounded.

DAMAGE
Infestations are usually of minor importance. Any effect
on tree growth is slight, even when noticeable colonies
develop.

Betulaphis quadrituberculata (Kaltenbach) ( 121 )
A locally common pest of birch ( Betula ). Widely
distributed in Europe.

Callaphis juglandis (Goeze) ( 122 )
Large walnut aphid
A generally common but minor pest of walnut ( Juglans ).
Colonies develop on the underside of the leaves, the
aphids causing slight yellowing and premature leaf fall.
Heavy infestations reduce the vigour of young trees but
attacks on established plants are of little or no
importance. The aphids (2-4 mm long) are bright
greenish yellow to yellow, marked with brownish black;
the wing veins of alates are dusky bordered.

DESCRIPTION
Apterous female: 1.3-2.0 mm long; greenish or
yellowish, sometimes marked with darker green or
yellow; abdomen with four rows of hairs along the back
and a series along either side, the longer hairs distinctly
capitate; siphunculi conical and stumpy; cauda broadly
rounded and subtriangular, projecting slightly beyond a
deeply cleft subanal plate. Alate: 1.5-2.2 mm long;
similar to aptera but with capitate hairs restricted to the
eighth abdominal segment; larger-bodied individuals
have the head, antennae, siphunculi and parts of thorax,
legs and abdomen dusky.

Callipterinella tuberculata (von Heyden) ( 123 )
syn. Aphis betularia (Kaltenbach)
Minor infestations of this widespread but locally
distributed species occur on birch ( Betula ), the aphids
occurring singly or in small groups on the leaves.
Colonies are sometimes noticed in the new foliage of
young trees but are not of importance. The aphids
(1-2 mm long) are basically greenish, with the body
variably patterned by dark sclerites, the darkened areas
often being extensive; the siphunculi are small, and the
cauda very short and inconspicuous.

LIFE HISTORY
Eggs overwinter on host trees and hatch in the spring.
Aphids then feed on the underside of the leaves,
individuals of the first generation developing into either
winged or wingless forms. Nymphs of subsequent
generations, most of which develop into wingless

121

121 Colony of Betulaphis quadrituberculata on Betula .