Biology Reference
In-Depth Information
384
385
384
Galls of rose leaf midge (
Dasineura rosarum
) on
Rosa
.
385
Larvae of rose leaf midge (
Dasineura rosarum
).
386
386
Gall of
Dasineura thomasiana
on young leaf of
Tilia
.
Dasineura rosarum
(Hardy) (
384-385
)
syn.
Wachtliella rosarum
(Hardy)
Rose leaf midge
A widely distributed midge, attacking both wild and
cultivated rose (
Rosa
). Adult midges appear in the late
spring, depositing eggs in unfurled leaves. Following
egg hatch, larvae develop within reddish-tinged, pod-
like galls, each formed from an expanded but still furled
leaflet. Up to 50 orange-coloured larvae occur in each
infested leaflet, causing the galled tissue to change from
green through reddish to dark brown. Individuals are
fully grown by the late summer; they then drop to the
ground where they overwinter and eventually pupate;
there is just one generation annually. Galled leaves often
occur in groups but any effect on plant growth is slight.
Dasineura thomasiniana
(Kieffer) (
386
)
Minor infestations of this midge are sometimes noticed
on lime (
Tilia
), the larvae feeding within distorted
leaves at the tips of young shoots. Affected leaves
remain folded, the veins becoming thickened and
deformed; buds are also affected. Each gall contains
several (2-3 mm long) whitish to orange or reddish
larvae. There are two or more generations annually.
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