Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 167

372 373

372 Young galls of sycamore leaf-roll gall midge ( Contarinia
acerplicans ) on Acer pseudoplatanus .

373 Sycamore leaf-roll gall midge ( Contarinia acerplicans )
damage to leaf of Acer pseudoplatanus .

374 375

374 Mature gall of lime leaf-stalk gall midge ( Contarinia
tiliarum ).

375 Section through gall of lime leaf-stalk gall midge
( Contarinia tiliarum ).

Contarinia petioli (Kieffer)
Poplar gall midge
Widely distributed in association with aspen ( Populus
tremula ) and, less frequently, white poplar ( P. alba ), the
orange-coloured larvae (each 3-4 mm long) developing
in galls on the young twigs and leaf stalks. Galls on the
leaf stalks are globular, and several are often fused
together; those on the twigs develop singly, each
becoming a localized lateral swelling. At maturity, each
gall develops a lateral aperture through which the causal
organism escapes to pupate in the soil. Although the
galls attract attention, particularly when present on
young trees, they are not considered harmful.

the soil and overwinter, there being just one generation
annually. Infested buds become greatly swollen and fail
to open, those attacked at a very early stage in their
development sometimes withering and turning brown.
Attacks are particularly common on yellow-flowered
cultivars, infestations reaching their peak by late June;
buds produced after mid-summer are unaffected.

Contarinia tiliarum (Kieffer) ( 374-375 )
Lime leaf-stalk gall midge
This moderately common midge forms globular galls
( c . 10 mm across) on the leaf stalks of lime ( Tilia ),
usually just before the leaf blade; galling also occurs on
the young stems. The galls are at first pale but later turn
red and, finally, black. They contain several (often up to
20) yellowish-orange larvae (up to 3 mm long), each
individual occupying a separate chamber. The larvae
commence their development in May or June and are
usually fully fed by the end of July; they then enter the
soil where they eventually pupate. Adult midges appear

Contarinia quinquenotata (Löw, F.)
A pest of day-lily ( Hemerocallis ); widely distributed in
mainland Europe, and discovered causing extensive
damage in southern England in the late 1980s. The
whitish larvae feed gregariously within the flower buds
during the early summer. When fully grown they enter