Mites - Pests of Ornamental Trees, Shrubs and Flowers - page 403

1087

CHRYSANTHEMUM

Epitrimerus alinae Liro
Chrysanthemum leaf rust mite
Free-living on greenhouse-grown Chrysanthemum , the
stems of which become russeted, notably around the
uppermost leaf stalks; such damage causes the leaves to
wilt and may result in premature leaf fall. The adult
mites are 0.16 mm long, with about 45 abdominal
tergites and a greater number of sternites.

CRATAEGUS

Epitrimerus piri (Nalepa)
Pear rust mite
The foliage of hawthorn ( Crataegus ) is sometimes
bronzed following the development of infestations of
this generally common mite. The pest sometimes occurs
on nursery stock but is more important in pear orchards,
russeting both the foliage and the developing fruits.

1087 Galls of Aceria longisetosus on underside of leaf of
Betula .

1088

Eriophyes pyri crataegi
See under Sorbus , p. 419

Phyllocoptes goniothorax (Nalepa) ( 1089 )
Hawthorn leaf gall mite
This mite causes a tight downward leaf-edge rolling on
hawthorn ( Crataegus ), and is often present on cultivated
plants. The rolled edges vary in colour from light green
to yellowish green, often with a reddish tinge, and
sometimes result in noticeable distortion of the leaf
blade. Galling is apparent from spring to autumn and is
often extensive, but not of significance, on unclipped
hedges. The causal mites are whitish, c . 0.18 mm long,
with about 54 abdominal tergites and sternites, and a pair
of small forwardly directed setae arising from tubercles
in front of the hind margin of the prodorsal shield. Forms
of this mite also occur in whitish erinea on the underside
of the leaves. These are often regarded as subspecies,
and include Phyllocoptes goniothorax malinus and P.
goniothorax sorbeus on crab-apple ( Malus ) and rowan
( Sorbus aucuparia ), respectively.

1088 Hornbeam leaf gall mite ( Eriophyes macrotrichus )
damage to leaf of Carpinus .

1089

1089 Galls of hawthorn leaf gall mite ( Phyllocoptes
goniothorax ).