After 60 years, the secret's still in the seaweed.

Brodifacoum (pronounced bro-die-far-koom) is a slow-acting poison used mainly for rodent and possum control. Pestoff® Rodent Bait 20R is a Vertebrate Toxic Agent registered under the ACVM Act 1997 to Animal Control Products Ltd of Whanganui, New Zealand

Brodifacoum is a slow acting toxin, which gives rodents and possums time to consume a lethal dose over 4 or 5 days before poisoning symptoms and the illness associated with poisoning occurs.

The delayed onset of symptoms ensures pests do not associate their illness with having eaten the bait; therefore the animals do not become wary of eating the bait.

• Choose the right product for the job and seek advice if required.
• Always use bait stations to ensure bait remains fresh and dry and prevent access by non-target species.
• Anticipate the problem rather than reacting to it. Preventative pest control is always cheaper, easier and more effective than remedial work.
• Expose all of the pests to the control measure at the same time and remove all other food options if possible.
• Follow label directions. This will improve results and minimise the risk to non-target animals.
• Replenish baits when they are consumed by pests and offer a generous amount of bait.
• Manage pest immigration by establishing and maintaining control buffer zones.
• Remember - Don’t touch the bait – use gloves to avoid human scent (and poisoning yourself!)

The Autumn Invasion (mouse in the house) so act early (Late summer)

• Establish Control Zone and a buffer for re-infestation
• Use enough Bait and refresh twice in the first months then pause
• Bait stations in cupboard, behind appliances, under floors, in ceiling space.
• 5m apart in high activity areas, 8-10m apart on outer perimeter.
• Place bait stations out of reach of children and pets.
• Check bait take weekly and replace eaten baits.
• Collect dead mice and dispose.

Farm & Domestic rats are usually Norway Rats known as the Stored Feed Pest. They breed from spring to late summer and targets Silage stacks, Grain storage, Pigs and poultry feed, Sheds & homesteads.

• Pulse baits from Sept to March
• After initial pulse go one pulse every 6 weeks
• Place bait stations according to activity levels
• 2-4 blocks per station
• Stations out of reach of children, pets and livestock.
• Establish a working perimeter (control zone)
• Talk to your neighbours (you can help each other)
• Target preferred habitat such as hedges, banks etc
• Bait stations 20-50m spacing

Forest Rats are usually Ship Rats. The critical time for control is September - January during bird nesting and fledgling season. Ship rats are very good climbers so it’s a 3D operation.

• More bait and less frequent visits/servicing
• Define treatment areas and set up buffer stations on perimeter at 25m spacing’s.
• Access tracks important
• 50m grid if possible
• Pulse in September, repeat 2x in November.
• Remove baits in January
• Consult with hunters and landowners (pigs may eat rats)
• Will take out stoats via secondary poisoning
• Permanent bait station placement is a good idea
• Philproof type bait station

For sustained control for low-medium numbers around Forest remnants, Riparian margins, Shelterbelts, Horticulture crops, small woodlots etc.

• The area should be discrete and not more than a few hectares.
• Pestoff should not be used for initial control unless preceded by other methods such as traps, shooting or acute toxins.
• 2-3 pulses per year, each comprising of 1 fill and 1 replace eaten bait.
• Establish bait stations one per 100m on bush boundaries or shelterbelts or 2 per hectare in forest.
• 700gm per station, replenish after 7-10 days.
• Repeat 1-2 more times per year

This varies between individuals depending on their susceptibility. As a guide however, work on 2 - 5 grams of bait for a mouse, 6 - 10 grams for rats and 100 - 200 grams for each possum.

For rats and mice, death will occur in 5 to 10 days and for possums, it may be up to 15 days.

If baits are fed continuously, the dominant animals will consume several lethal doses each before symptoms occur and this may leave no bait remaining for juveniles and smaller individuals.

This can be overcome by using pulse baiting which breaks the baiting programme into specific baiting and non-baiting periods, allowing time between baiting periods for poisoned animals to succumb.

Pulse baiting is the main method used specifically for delivering anticoagulant baits in bait stations. It involves one fill and up to two top-up refills over 3 - 4 week period, followed by 6 to 8 weeks of no baiting before another pulse is applied.

You do not need a license to purchase or use brodifacoum. However, you will need to meet requirements for its use, storage and disposal, as well as signage. (For guidance see the packaging go to www.epa.govt.nz and search for vertebrate pest control.)

Most brodifacoum used in forest areas comes in pellets made from cereal and containing 0.002% toxin and are coloured green or blue and must be used in bait stations. They can be wax-coated to better protect them from weather when in the field. When rodents particularly are targeted for control, purpose-designed brodifacoum bait blocks and bait stations, in a range of shapes and sizes, may be used.

The risk to people is extremely low, as a large amount has to be eaten to fall ill. A lethal dose for humans is estimated to be about 15 mg of pure brodifacoum per kg of body weight. This equates to approximately 5 kg of bait for a toddler (ten bait stations’ worth) and about 50 kg of bait for a 70 kg adult. It is estimated that a 70 kg adult would have to consume at least 50 2-gram baits before effects on blood coagulation would be measurable.

Contact the National Poisons Centre, in an emergency 0800 764 766.

Non-target animals, such as native birds, livestock, domestic pets and feral animals are at low risk of being poisoned by eating baits directly.

Cats are unlikely to eat the bait but some dogs and most livestock will attempt to eat baits if they can gain access, so ensure baits are in bait stations and bait stations are out of their reach at all times.

If an animal or pet displays the following symptoms take it to the nearest veterinary clinic, where they can administer Vitamin K1, an effective antidote.

Non-target animals, such as native birds, livestock, domestic pets and feral animals are at low risk of being poisoned by eating baits directly.

Cats are unlikely to eat the bait but some dogs and most livestock will attempt to eat baits if they can gain access, so ensure baits are in bait stations and bait stations are out of their reach at all times.

If an animal or pet displays the following symptoms take it to the nearest veterinary clinic, where they can administer Vitamin K1, an effective antidote.

Brodifacoum poses a low risk to dogs only generally if they scavenge poisoned rodents or possums. Keep dogs well-fed and under strict control (muzzled if necessary) to prevent them from scavenging dead animals.

If your dog eats poison or a poisoned carcass induce vomiting with washing soda crystals and take it to the nearest veterinary clinic

Do not rely on the treatment. Prevention is the only sure way of protecting animals and pets from poisoning.

Livestock exposed to brodifacoum should not be sent to slaughter or sold. Research has shown that anticoagulant toxins stay in the body for many months. It is an offence under the Meat (Residues) Regulations Act to send animals for slaughter that contain chemical residues above prescribed limits. In the case of poisons any detectable residue is considered a violation. If you decide to send contaminated livestock to the meatworks, you must contact the MAF veterinarian at the processing plant before freighting the animals.

If dairy cattle become exposed to brodifacoum, immediately notify the dairy supply company. If deaths occur in sheep or cattle, the entire flock or herd should be withheld for nine months.

Please notify your Regional Council if you suspect livestock has been exposed to poison baits. They may have to notify the Medical Officer of Health.

Under the Meat (Residues) and the Game Regulations MAF has advised that, feral animals intended for sale to a game pack house cannot be hunted in areas where poisons have been laid.

Appropriate declarations have to be supplied to establish that the animals have been obtained from areas free of contaminants. Therefore, landowners and hunters are advised not to sell feral animals taken from an operational area within nine months after the termination of poisoning within 2 km (5 km for feral pigs) of a poisoning operation boundary. The policy applies for feral animals intended for personal consumption.

• Brodifacoum is not soluble in water and binds strongly to soils, making it almost immobile. It will degrade slowly in soils with pH5.5 to pH8 under aerobic or flooded conditions and plants do not absorb it.
• Baits are only used in bait stations, so it is unlikely the poison will be found in water.
• Brodifacoum can remain in animal livers and may present a danger to other species through both secondary and tertiary poisoning. The half-life of brodifacoum in possum livers is about 36 weeks.

Rats carry a wide range of pests and diseases, which can threaten humans and livestock. These included: Fleas, lice and tapeworms that can transfer to man or animals.

• Tapeworms may cause capillariasis and toxicariosis. Protozoa causing cryptosporidiosis and toxoplasmosis.
• Bacteria causing leptospirosis, listeriosis, pasteurellosis and melioidosis.
• Leptospirosis icterohaemorrhagiae causes Weils disease in humans, which, produces flu-like symptoms, and in rare cases, death.
• Rickettsia, which causes Q fever.
• Viruses, which can cause Hantaan fever in humans.
• Leptospiroses in rat urine present a health risk to humans – Weils disease.
• Rats may spread foot and mouth disease, which is why control measures are essential on infected farms.

Because of the threats posed to humans from a range of rodent-borne pests and diseases, good hygiene is important. Protective clothing should always be worn. Hands must be washed after work and before any food or drink is consumed.

Anyone who has been exposed to rodent-borne threats should inform their doctor when seeking medical advice.

The four species of rodents in New Zealand are all from the family Muridae: kiore (Rattus exulans), Norway rat (Rattus norvegicus), ship rat (Rattus rattus) and house mouse (Mus musculus). Kiore, which is the smallest of the Rattus species in New Zealand, has been here the longest. Norway rats, which are the largest rats, are often found near water. They colonised from ships and remain a potential source of new island invasions. Ship rats are the most widespread mammal on the New Zealand mainland, but are not often seen as they are nocturnal, arboreal and shy. The established New Zealand ship rats are all of the Oceania form, which differ in karyotype and possibly behaviour from the Asian form, which has more recently reached New Zealand on Asian fishing boats. The house mouse is one of the most widespread mammals of the world.

All four species are generally nocturnal and have excellent senses of smell, touch, hearing, and taste. Although rodents readily explore new surroundings, they are generally wary of any new objects in a familiar environment. This can substantially reduce initial trapping success or bait acceptance.