An integrated
pest management programme for rodents requires
three steps.
| Steps
|
Task |
|
|
A
continuous monitoring programme
to control rodents when numbers
are small. |
|
|
Reduce feed and water sources
by practising good sanitation
and excluding populations from
buildings and food sources |
|
(
Control ) |
Reduce
the population |
|
|
| |
|
|
-
Step 1: Monitor for rodents
Rodents leave droppings where they are active.
Check along walls, behind objects or near
food supplies such as spilt grain.
• Look for gnaw marks
Rodents’ teeth grow constantly so they
must gnaw to keep their teeth down. They will
chew on leather, wood, plastics and rubber
plus many other materials. Damage to wiring,
which may lead to fires, and hoses on farm
equipment is common.
• Check
for burrows
Rats will burrow along foundations,
through floorboards and into wall spaces.
Mice burrows can also be monitored in the
paddock by walking a straight line for 100
metres and counting the number of burrows
found. If they are active, five holes in 100
metres is the equivalent of 1000 mice per
hectare. You can mark holes with talcum powder
and then check the next morning to see if
there are fresh tracks.
• Check
for runways and smudge marks
These are the rodent’s calling
card. Look for dust-free areas along walls
and behind storage materials. Look for wood
chips around boards, bins and crates. Persistent
musky odours are also positive signs of rodent
infestation. Smudge marks may be found on
pipes or rafters where dirt and oil from fur
leave a greasy film.
• Use
monitoring cards
Canola or linseed oil impregnated
bait cards can be used to monitor mice in
the paddock. Peg out cards, leave overnight
and monitor how many have been eaten. Remember
if there are competitive feed sources available
this could underestimate the number of rodents.
- Step 2:
Sanitise. Reduce feed and water and seal entry
points
The second step is to reduce feed and water
sources and look at methods to exclude rodents
from buildings on farm.
• Eliminate
their habitat
Eliminate potential nesting sites,
food supplies and water. Keep feed in rodent-proof
bins or covered cans and reduce access to
water such as leaky taps, open water troughs,
sweating pipes and open drains where practical.
Reduce long grass and vegetation around buildings,
clean up spilled feed, and remove loose wood
and garbage. Populations build when food,
water and nesting sites are readily available.
• Prevent access
Good sanitation means preventing
rodents from accessing your farm buildings.
Remember, a mouse needs only a 6 mm opening
to gain access and rats need an opening the
size of a 10 cent piece. Cracks around door
frames, under doors, broken windows, water
and utility access points, vents and holes
surrounding feed augers are all potential
points of entry.
-
Step 3: Control. Reduce the population
Without good sanitation and physical measures
to exclude rodents the population will return
with time.
Control of mice can be achieved by using traps
for small populations owing to their curious
nature. Rats, being more cautious are less
likely to be trapped and generally require
baiting. Baits are necessary for control of
moderate and larger populations of both rats
and mice.
There are different
types of baits for use in different situations.
There are three basic types of rodenticides;
Type
of rodenticide |
Number
of feeds required |
Effect
on rodent |
Risk to non-target
species |
Active/Brands |
| Acute poisons |
Require only
a single feed to kill |
Rodents die quickly which
leads to bait shyness |
High risk to
non-target animals |
strychnine, zinc phosphide
and thallium |
| Single dose anti-coagulants
|
May require only
a single feed for delayed kill |
Rodents continue to feed
over several days even though they have
already consumed a lethal dose. die
3-8 days |
Medium risk to non-target
animals |
brodifacoum
bromadialone
flocoumafen |
| Multiple dose anti-coagulants
|
Require multiple feedings
for delayed kill |
Rodents continue to feed
over several days as the effect builds.
die 3-8 days |
Low risk to non-target
animals |
Coumatetralyl
(Racumin) |
| Product
Name |
Active
Ingredients |
Type |
Label |
Racumin
8 Rat and Mouse Rodenticide
|
8
g/kg coumatetralyl |
Rodenticide |
|
| Racumin
Blocks |
0.37 g/kg coumatetralyl
|
Rodenticide |
|
| Racumin
Paste |
0.37 g/kg coumatetralyl |
Rodenticide |
|
When an acute poison is used, rodents die
quickly after consuming the bait. Other rodents,
observing the death of their fellow rodent,
will realise that the bait is deadly and will
not feed on it. Both single and multiple dose
anticoagulants have a delayed effect to avoid
what is known as “bait shyness”.
This delayed effect means that the symptoms
of poisoning are not associated with the bait
consumed.
• How anticoagulants
work
Anticoagulant baits work by interfering with
the blood clotting mechanism in rodents. Once
the rodenticide has built up to a certain
level in the body, the rodent dies of internal
bleeding. Studies show that rodents do not
feel pain when dying.
• Single
dose anti-coagulants
as the name implies, require only a single
feed to kill. However, as they have a delayed
effect, rodents will live for several days
after the initial feeding, returning to the
bait and consuming much more than the lethal
dose they require. This means that they may
contain high levels of toxic residues in their
body making them an increased high risk to
non-target animals such as wildlife and farm
dogs if they are eaten. The anti-coagulant
effects of the bait can then be transferred
to the dog.
• Multiple
feed anticoagulants
such as Racumin, require multiple feedings
as they are not as persistent in the body.
This means that by the time that rodents are
dying or dead, the residues they contain are
a very low risk to a non-target animal. They
can be used long term to gain control of a
rodent population.
Both single and multiple dose anticoagulants
take at least three days before symptoms occur,
and death results 3 to 8 days after 1st feeding
as they feed the most. It is important for
baiting to continue for at least 2 weeks to
control an average sized population. More
dominant rats will be the first to die, they
are followed by less dominant rats as they
gain access to bait after the dominant rats
die. |
|
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