Agriculture Reference
In-Depth Information
Fig. 206
Antenna of female upland click beetle,
Ctenicera cupreus.
Fig. 207
Adult of
Glischrochilus hortensis
(xlO).
metallic green or dark coppery, sometimes with
partly yellowish-tinged elytra; the antennae of
males are long and each bears eight prong-
like projections; the antennae of females are
serrated, with most flagellar segments triangular
(Fig. 206).
adults and larvae often cause damage to oilseed
rape, white mustard and other brassica seed
crops, including cabbage and swede. Adults bite
into the buds and this leads to abortion and,
potentially, loss of yield. On winter rape, which
has considerable powers of compensation and is
usually past the vulnerable bud stage before the
majority of adults emerge from hibernation, eco-
nomic damage is rare; spring rape is more vul-
nerable and also more susceptible, as it flowers
later in the season and is less robust. Larvae,
which feed in the open blossoms, may also cause
abortion of young pods but such damage is of
little or no significance. In recent years, large
numbers of young adults reared on oilseed rape
crops have migrated to, and caused damage to,
autumn-grown vegetable crops, especially the
developing heads of calabrese and cauliflower;
the beetles also invade various ornamental flow-
ering crops in search of pollen, and have often
then become a local nuisance.
Family NITIDULIDAE
Glischrochilus hortensis
(Fourcroy)
Adults of this relatively common beetle are
sometimes reported in summer congregating on,
and causing minor damage to, the ripening grains
of bird-damaged cobs of maize or sweet corn.
Similar accumulations of beetles are reported on
mechanically damaged or diseased turnip roots
and on outdoor tomatoes; locally significant
damage to the ripening fruits of autumn-fruiting
strawberries is also reported. Such attacks are
most likely to occur in hot, dry weather, when
the beetles seek suitable sources of moisture.
Larvae feed on the ground on rotting vegetable
matter and are of no pest status. The adult bee-
tles are 4-6mm long, black and shiny, with four
orange-red spots on the elytra
(Fig. 207).
BIOLOGY
Adults appear in the spring, from late April or
early May onwards, and are usually active until
June. They often congregate in large numbers on
brassicaceous plants, including oilseed rape and
weeds such as
Sinapis arvensis,
where they bite
into the buds and opening flowers and feed on
the anthers and exposed pollen. Eggs are laid in
the flower buds and hatch about 7-10 days later.
Meligethes aeneus
(F.)
Pollen beetle
This generally abundant beetle is associated
mainly with members of the Brassicaceae. The
