PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Obtain advice.
– Regulations under the relevant Acts prescribe
methods of control to be adopted.
– If an infestation develops on a property, it must be
reported to the nearest administering office.
– Log onto State/Territory websites (page xiv).
Cultural methods. Cultivation of egg pods
particularly in agricultural areas could destroy
eggs, but is not very effective as most egg pods
will be missed.
Biological control.
Natural enemies. All stages of locusts may be
attacked. The degree of control depends on
number of parasites and predators, size of the
locust population and the season.
– Parasites include various flies, and wasps.
– Predators include birds, small marsupials, feral
pigs, dogs and foxes, lizards, frogs, ants, bugs, ants,
spiders.
– Diseases include various fungi, nematodes and
protozoa especially in high rainfall areas.
Commercial biocontrol agents.
– Green Guard (Metarhizium anisopliae var.
acridium) has been developed from a naturally
occurring fungus as a biocontrol agent for organic
properties and environmentally sensitive areas.
This fungal strain only attacks locusts and
grasshoppers and is harmless to all other kinds of
organisms. Fungal spores are suspended in a
mineral or vegetable oil (to prevent drying out) and
sprayed onto locusts using conventional aerial and
ground spraying equipment. The live spores
germinate on the body of the insect, grow through
the skin and eventually kill up to 90-95% of locusts
after 7-20 days, but locusts can still damage plants
for a number of days after they are infected. Ants
and other scavenging insects eat the dead insects
and so they are often difficult to find. Further
information and a newsletter are available on the
APLC website.
Physical and mechanical methods.
In gardens netting or shade cloth can be used to
protect special or expensive plants.
Insecticides.
Chemical control is difficult. Specific areas or
bands or swarms are targeted (Table 37). Blanket
spraying over large areas is not carried out.
Timing.
– Hopper bands. Treating small areas of dense
masses of hoppers can effectively control
potentially damaging populations. However, more
than 1 application may be needed because eggs may
hatch over a period of several weeks. Coordinated
use of appropriate sprays on hopper bands can
reduce an infestation from a potential major plague
to a minor outbreak. Should control measures taken
against hoppers fail, swarms may migrate from the
breeding area and a plague may develop.
– Control of flying locusts is beyond the scope of
an individual landholder. Adult locusts can be
controlled by treating swarms with aerial ULV
applications of an insecticide. Differential Global
Positioning Satellite (DGPS) units are fitted to spray
aircraft to ensure precise application within target
areas in pastoral areas inland. Crop protection is
primarily the responsibility of the grower who
should report incidence of locusts and obtain
information from the local council or appropriate
organization.
There are ‘no spray’ buffer zones of 1.5km
between sprayed areas and sensitive areas
downwind, eg residences, dams and waterways.
In addition no pesticides are applied within 5km
of beehives or crops being pollinated by bees.
Impact of pesticides on the environment, eg
researching the impact of pesticides on dunnarts
(Sminthopsis macrour), a small marsupial that
looks like a hopping mouse. Dunnarts gorge on
locusts and store body fat for the coming winter.
So they will ingest a small amount of pesticide.
Application equipment. Locust control is
through a combination of ground and aerial
pesticide spraying (landholders and APLC).
Pesticide application methods are improving all
the time, eg drift reduction and improved
adherence to regulations and other safety
requirements.
The APLC also provides advice to landholders
and state agencies. APLC becomes involved in
control when the magnitude of control is beyond
the realms of the individual landholder or stage
agency and where particular groups of locusts
are a threat to interstate agriculture.
Table 37. Australian plague locust – Some insecticides and biocontrol agents.
What to use?
CHECK WITH YOUR LOCAL AUTHORITY
Registered insecticides vary from state to state and
depend on the situation, crop, etc.
Group 1A, eg carbaryl
Group 1B, eg chlorpyrifos, fenitrothion, maldison
Group 2B, eg Regent , various (fipronil)
PERMITS MAY BE REQUIRED
Group 3A, eg Tempo (beta-cyfluthrin) is registered for control
of grasshoppers on turf, native plants, ornamentals
in domestic, and certain other situations.
Fungal biological control agents
GreenGuard TM (Metarhizium anisopliae var. aecidium.) -
various formulations
When & how to apply?
Locusts can be controlled chemically at the nymph
(hopper bands) and adult stages (swarms). Some
insecticides may be too persistent for use on some crops
and in some situations. Withholding periods must be
observed.
Various formulations of GreenGuard TM is used by APLC
against the APL, migratory locust, spur-throated locust
and wingless grasshopper in situations where insecticides
cannot be used to control locusts, eg certified organic
pastoral properties or environmentally
sensitive areas.
Insects and allied pests - Orthoptera (locusts) 185