Insects of Southern Australian Broadacre Farming Systems - Grains ...

The distinctive appearance of adult weevils make them
unlikely to be confused with other beetles. However,
distinguishing between the many species of weevils can
be difficult. Mandalotus weevil (Mandalotus spp.) adults
in particular are highly variable in appearance.
Distribution, pest status and risk period
Weevils can be found in a wide range of habitats and
many are known as pests of agriculture, stored products,
horticulture and forestry. They feed on vegetable parts
including shoots, buds, leaves, roots, wood and bark.
Some also feed on stored grain and vegetable products.
As larvae are legless, they are restricted in their
movement and distribution. They may be restricted
above ground (e.g. vegetable weevil) or confined
underground (e.g. Desiantha weevil). Adults are more
mobile and can be winged and active flyers, or wingless
and walk or march en masse. Adults and larvae can both
cause damage depending on the crop and time of year.
Monitoring/sampling
A variety of sampling techniques can be used depending
upon the habitat. For example, pitfall traps can be used
to sample ground-dwelling weevils. For above-ground
species, visual direct searches are appropriate. Often,
direct searches may need to be undertaken at night
when many species are active.
Damage symptoms
Scalloping on
leaf edges
Ring barking
plants at ground level
results in lopping
Insects of Southern Australian Broadacre Farming Systems Identification Manual and Education Resource © 2012
Bullet hole
on leaves
28
Thinning of plants
and bare patches due to
underground feeding on
roots/seeds
SECTION 4 COMMON Pest, Beneficial and exotic Species