Weevils are a diverse group of beetles that are commonly
found in Australian grain crops. Adult weevils appear very
different to the larvae. Adults have a hardened body, six
prominent legs and an elongated, downward curved head
forming a ‘snout’. The larvae are legless, maggot-like in
shape and may be confused with fly larvae. Weevil larvae
possess a small, hardened head capsule.
Crop weevils feed on vegetative parts of crop plants including
the roots, stems, shoots, buds and leaves. Both adults and
larvae can be damaging to plants, depending on the species,
crop type and time of year. Typical feeding damage commonly
observed is scallop-shaped holes along the edges of leaves.
Weevils can be difficult to control with chemicals due to
their secretive habits. Several species are also patchy in
their distribution within paddocks. For some species, seed
treatments and foliar insecticides can provide a level of
control. Weevils are typically favoured by minimum tillage
and stubble retention. Cultivation, burning and reducing the
amount of stubble will reduce the suitable habitat for weevils
and reduce their number.
Identification of crop weevils is important when making
control decisions. The distinctive appearance of weevils
makes them unlikely to be confused with other beetles.
However, distinguishing between the many species of weevil
is challenging. This guide is designed to assist growers in
identifying the most commonly observed weevils found in the
southern and western cropping regions.
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South, West, North