Biology Reference
In-Depth Information
Messa hortulana
(Klug) (
989-990
)
A locally distributed, leaf-mining and mainly
parthenogenetic sawfly associated with black poplar
(
Populus nigra
), infestations occurring occasionally on
ornamental trees. The larvae (up to 10 mm long) are
whitish and shiny, with a brownish-black head, a
blackish prothoracic plate and black plates between the
thoracic legs. They occur from May or June to July,
each feeding within a brown, blister-like, frass-filled
blotch. Mines develop from the leaf margin, and cause
slight distortion of the leaf blade. If attacks are heavy,
several eggs may be deposited in the same leaf, mines
then eventually merging to occupy most if not all of the
available tissue. Larvae are fully fed in about four
weeks. They then vacate their mines to pupate in
cocoons formed in the ground. The adult females are
4.0-4.5 mm long, stout-bodied and mainly black, with
white tegulae and yellowish-white knees, tibiae and
tarsi. They usually emerge in May, there being just one
generation annually.
Messa nana
(Klug) (
991
)
syn.
M. quercus
(Cameron)
Infestations of this widely distributed, mainly
parthenogenetic species occur on birch (
Betula
),
especially downy birch (
B. pubescens
). The larvae (up
to 8 mm long) are whitish to yellowish white, with a
brown head and prothoracic plate, and black plates
between the thoracic legs. They form brown, frass-
filled blotches on the leaves, feeding from July or
August to September. Adults are similar to those of the
previous species; they appear in May and June.
990
989
989
Larva of
Messa hortulana
.
990
Mine of
Messa hortulana
in leaf of
Populus
.
991
991
Mine of
Messa nana
in leaf of
Betula
.
Search WWH ::
Custom Search