Mites - Pests of Ornamental Trees, Shrubs and Flowers - page 404

CYTISUS FAGUS

Eriophyes genistae (Nalepa) ( 1090 )
Broom gall mite
A locally common pest in parks and gardens, breeding
throughout the spring and summer in galled buds of
broom ( Cytisus ) and greenweed ( Genista ). Young buds
are invaded in the spring, each then developing into a
tight cluster of fleshy, pale green lobes, with a downy
coating of whitish hairs. The galls measure about
20-30 mm across at maturity, and often persist on
infested plants for several years. Infested shoots are
stunted and, if attacks persist, bushes are severely
disfigured. Mites inhabiting the galls are brownish,
c . 0.13 mm long, with about 70 abdominal tergites and
sternites, and a pair of backwardly directed setae arising
from tubercles on the hind margin of the prodorsal
shield.

Aceria stenaspis (Nalepa) ( 1092 )
syn. A. stenaspis plicans (Nalepa)
A locally common pest of beech ( Fagus sylvatica ), the
mites causing considerable malformation and stunting
of young leaves, and death of opening buds. The mites,
which breed within the shelter of the galled tissue
throughout the spring and summer, are whitish and
c . 0.14 mm long, with about 75 abdominal tergites and
sternites. Damage frequently occurs on garden hedges
but is often overlooked. A species of Acaricalus is also
associated with leaf deformation on beech, but may be
merely an inquiline in buds damaged by Aceria
stenaspis .

Aceria stenaspis stenaspis (Nalepa) ( 1093 )
This subspecies breeds in marginal leaf-roll galls
formed on the extreme edge of infested beech ( Fagus
sylvatica ) leaves. The tissue rolls over the upper surface,
to form a tight, hair-lined tube 1-2 mm in diameter;
distortion and discoloration may also spread onto the
leaf blades. The galls occur from late April or May
onwards, changing from green to brown as they mature.

EUONYMUS

Eriophyes convolvens (Nalepa) ( 1091 )
Spindle leaf-roll gall mite
This mite causes an upward leaf-edge rolling on spindle
( Euonymus ). Attacks on wild European spindle
( E. europaeus ) are often extensive, and galling is
sometimes also noted on cultivated bushes. Although
unsightly, galls do not affect plant growth. The mites are
whitish and relatively small ( c . 0.11 mm long), with
about 60 abdominal tergites and sternites, and a pair of
small, forwardly directed, convergent, setae arising
from tubercles in front of the hind margin of the
prodorsal shield.

Eriophyes nervisequus (Canestrini) ( 1094 )
Beech leaf-vein gall mite
A common species, forming hairy, white to brownish
ridges along the major lateral veins on the upper
surface of leaves of beech ( Fagus sylvatica ). The galls
are most often noticed in June, during the early stages
of development before the hairs darken. Mites
inhabiting these galls are c . 0.13 mm long, with about
60 abdominal tergites and sternites, and a pair of
backwardly directed setae arising from tubercles on the
hind margin of the prodorsal shield.

Eriophyes nervisequus fagineus Nalepa ( 1095 )
Beech erineum gall mite
This locally common subspecies is responsible for the
formation of conspicuous erinea between the major
veins on the underside of beech ( Fagus sylvatica )
leaves. The galls develop throughout the summer
months, commencing as pale patches of enlarged, club-
shaped hairs, amongst which various stages of the mite
may be found; the erinea soon turn red and finally
brown. Heavy infestations cause young leaves to curl at
the edges.