Biology Reference
In-Depth Information
346
347
346
Lesser strawberry weevil (
Otiorhynchus rugosostriatus
).
347
Larva of lesser strawberry weevil (
Otiorhynchus
rugosostriatus
).
Otiorhynchus rugosostriatus
(Goeze) (
346-347
)
Lesser strawberry weevil
Although most frequently reported as a pest of
strawberry, this widely distributed and locally common
weevil also attacks pot plants and ornamental shrubs,
the adults notching the edges of expanded leaves and
the larvae feeding on the roots. Damage is most
commonly reported on
Begonia
,
Cyclamen
, lilac
(
Syringa
), primrose (
Primula vulgaris
) and privet
(
Ligustrum vulgare
). Adults (6-7 mm long) are blackish
to reddish brown, and strongly sculptured; they are most
numerous from June to September. The larvae, which
feed throughout the autumn and winter, are similar to
those of
Otiorhynchus sulcatus
(see p. 160) but smaller,
reaching a maximum length of about 8 mm.
DESCRIPTION
Adult:
1.5-2.4 mm long; body stubby and egg-shaped;
brownish black, with yellowish hairs; antennae
yellowish red.
LIFE HISTORY
Adults occur in June. They then attack the young shoots,
stems and branches of host trees. Breeding occurs in
distinctive galleries formed beneath the bark of the
trunks and larger branches, the beetles excavating two-
branched egg chambers that run vertically upwards and
downwards from the initial entry hole, and from which
larval galleries eventually arise. The latter, each up to
50 mm long, emerge at right angles but soon turn
vertically. There is one generation annually, but two are
possible in favorable locations.
Phloeosinus thujae
(Perris)
Thuja bark beetle
A widely distributed primary and secondary pest of
Cupressaceae, including coastal red wood (
Sequoia
sempervirens
), common juniper (
Juniperus communis
),
Italian cypress (
Cupressus sempervirens
), Sawara
cypress (
Chamaecyparis pisifera
), Wellingtonia
(
Sequoiadendron giganteum
) and white cedar (
Thuja
occidentalis
). Most numerous in the warmer parts of
central, eastern and southern Europe.
DAMAGE
Attacked established trees are weakened, but
infestations on hedging plants and on young trees being
raised in nurseries are most serious. When adult beetles
bore into green tissue this often results in the death of
shoots.
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