Biology Reference
In-Depth Information
Chapter 3
Mites
Family
PHYTOPTIDAE
(gall mites)
very noticeable from September onwards. Such galls
are often abundant in hedgerows. They are also often
numerous on ornamentals and nursery stock, affecting
both the appearance and potential structure of young
plants. The causal mites are whitish and elongate
(
c
. 0.3 mm long), with numerous abdominal tergites and
sternites, and a pair of short, anterior (frontal) setae and
a pair of longer posterior (dorsal) setae on the prodorsal
shield.
Phytoptus avellanae
Nalepa (
1071
)
syn.
Phyllocoptella avellanae
(Nalepa)
Filbert bud mite
Associated with hazel (
Corylus
), on which it induces the
formation of greatly enlarged buds ('big buds'). The
mites breed within the shelter of the galled buds
throughout the autumn and winter. In early spring,
female mites migrate from the galls to invade the leaves,
where further eggs are laid. The eggs produce active
protonymphs that feed and eventually moult into more
or less sedentary deutonymphs; these, unlike adults and
protonymphs, are distinctly flattened and have few
abdominal tergites. In late June or July the summer
deutonymphs moult into 'normal' adults. These invade
new terminal buds. These buds then swell and become
Phytoptus tetratrichus
Nalepa (
1072
)
This species forms tight upward leaf-roll galls along the
edge of the leaves of various kinds of lime (
Tilia
).
The galls cause slight distortion but are less noticeable
than those formed on lime by the midge
Dasineura
tiliamvolvens
(p. 180).
1071
1072
1071
Gall of filbert bud mite (
Phytoptus avellanae
).
1072
Galls of
Phytoptus tetratrichus
on leaf of
Tilia
.
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