Agriculture Reference
In-Depth Information
10
Urban Timber Pest Beetles: Risks and
Management
Donald Ewart*
Independent Consultant, Australia
Introduction
beetles exist, any timber that is suitable for
them will eventually be visited. In Australia,
attack by
Lyctus
on susceptible hardwood is
regarded as 'inevitable' (Peters
et al
., 2002).
Thus inspection of an infestation and
assessment of at-risk timber is an important
part of sustainable management.
Timber is a diffi cult resource for insects and
even though it is largely constructed from
polymers of sugars, it is hard to digest. Few
species can exploit a timber diet. Timber
pests are necessarily specialist feeders and
are often very particular about the species of
timber and presentation of their food.
Sometimes timber pests are well organized,
such as the termites, but mostly they act
alone, with cooperation rarely extending
beyond the sharing of exit paths.
The timber-feeding habit occurs across
several families within the Coleoptera, and
they are known to exploit live trees, dead
and nearly dead trees, new timber, old
timber and timbers with varying levels of
decay. Common names are widely employed
to describe the pest species but such names
are often only useful in limited geographic
areas and should be avoided. For example,
the common name powder post beetle is
widely used to describe lyctids, but in
north-east America can also describe
various other Anobiidae, Bostrichidae and
Lyctidae (Liebherr, 1976).
All species of adult beetles that are
reported as pests of timber can fl y and use
this ability to locate suitable food from its
odour trail. The ability to detect odour trails
in the air means that, in areas where pest
Timbers and Timber Products
Timber is the wood of a tree that has been
cut, shaped and usually dried so that it is fi t
for structural or for decorative use (Desch
and Dinwoodie, 1996). The process of
transforming wood into timber changes its
density, moisture content and extractive
content and hence often increases its risk of
infestation. A surface coating or preservative
may be used to effectively manage the risk.
Increasingly, the timber industry is moving
to manufactured products such as veneer
lumber, plywoods and fi breboards that have
risk profi les different from their parent
timbers. Manufactured timbers with a high
glue content or glueline additive pesticides
are generally immune from beetle attack but
a glueline alone is no defence (Serment,
1977). Further, the susceptibility of timbers
from a tree species is not constant. It varies
according to how and where the tree grew
and is generally higher for trees from
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