PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Australian plague locust
Outbreaks of the Australian Plague Locust (APL)
are common throughout south eastern Australia.
Plagues also occur in WA. The APL can easily
cause costly disruption to agricultural production
and urban horticulture in rural towns. It is not so
much a problem in coastal cities and towns.
Scientific name
Chortoicetes terminifera (Order Orthoptera).
Native to Australia.
Host range
APL prefers grasses such as pasture and related
winter and summer cereal crops, but will eat any
green plant material if grass is not available, eg
sorghum, lucerne, vegetables and orchard trees.
Description & damage
Adults are 20-45 mm long. Forewings with
mottled markings, hindwings with black tips
(otherwise clear); shank of hindlegs scarlet. Males
are usually smaller than females. The general
color is brown, but green forms are common in
dispersed populations. Hoppers (nymphs)
resemble adults but lack fully grown wings. Bands
of hoppers can be so dense that they can be seen
from the air as an advancing front eating out
vegetation as they progress.
Damage. Hopper and adults chew pieces out of
leaves and stems often all that remains is the
midrib and stems. Pasture and young crops can
be invaded by hoppers and completely defoliated.
Orchards, vegetables, other crops may be
damaged in closely settled districts. Home
gardens in urban areas usually only suffer minor
damage.
General. APLs migrate in huge swarms
denuding large areas of vegetation. A single swarm
may contain millions of locusts. APLC have
calculated that a 1 km swarm of APL could eat
between 0.8 and 10 tonnes of vegetation per day
depending on swarm density. Losses may amount
to several millions of dollars during a plague
unless organized control action is taken.
Diagnostics. Adult APLs are relatively easy to
identify from the black tips on their hindwings and
red shanks of their hindlegs (Fig.120 below).
Hoppers are more difficult to identify. Good
descriptions are available:
State/Territory Department Fact Sheets.
Australian Plague Locust Commission (APLC)
www.daff.gov.au/animal-plant-health/locusts
Zborowski. 1998. Field Guide to the Locusts and
Related Grasshoppers in Australia. APLC, GPO
Box 858, Canberra, ACT 2601.
If still in doubt send specimens to your local
diagnostic service (page xiv).
Fig. 120. Australian plague locust (APL) (Chortoicetes terminifera). Left: 5 nymphal stages of hoppers.
Size and orientation of wingbuds differentiates stages. Right: Adult APL. Photo NSW Dept of Industry and Investment.
Fig. 121. Locusts. Left: A swarm of locusts shelter in the shade of a tree during the heat of the day.
Right: Damage to sorghum, probably by migratory locusts. Photo NSW Dept of Industry and Investment.
182 Insects and allied pests - Orthoptera (locusts)