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Overview
Most of the toxins below are anticoagulants. The main benefit of these over other toxins is that the time it takes to work means that rats and possums do not associate the effects with their normal feeding habits.
Common anticoagulants used in New Zealand for rodents and possum control are either single dose (second generation) or multi dose (first generation). They work by blocking the Vitamin K cycle and preventing blood clotting.
First generation toxins generally break down quicker in the environment and require higher concentrations of their active ingredient and consecutive intake (i.e. multiple feeds) over days (e.g. every 4-5 days over 1-3 weeks [check manufacturers’ labels to confirm]) to get a lethal dose. They are less toxic than second generation toxins. It is often useful to pre-feed with a similar looking non-toxic pellet or block to habituate possums, rats and mice to stations to ensure a lethal dose of toxic baits is taken before symptoms set in.
Second generation toxins are far more toxic than first generation. As a result they are generally applied in lower concentrations in baits, are lethal after a single feed and effective against rats and mice that may be resistant to first generation toxins. They can take longer to break down in the environment. However, because there are generally multiple individuals present, these toxins are pulsed (i.e. stations are refreshed every 3-4 weeks) so that lethally poisoned animals habituated to the stations do not return to take more bait than necessary.
There are a number of other vertebrate pesticides that work differently to anticoagulants. An example is cholecalciferol, which occurs naturally as Vitamin D3. Vitamin D maintains calcium balance in bodies by enhancing the absorption of calcium from the gut and kidneys. Doses of cholecalciferol lead to too much calcium in the blood. The body’s ability to maintain proper calcium levels must be overwhelmed before cholecalciferol becomes toxic. This is why it is a multi feed toxin as rodents must eat several doses of this rodenticide to get a lethal dose. Cholecalciferol is known as an acute toxin. It causes appetite loss within 20 minutes (hence the need to pre-feed).
Summary of baits
Below is an at-a-glance summary of commonly available vertebrate pesticides in New Zealand. For more details about each one, see below the table.
| Toxin | Effective on | Single or multi feed? | Advantages | Disadvantages | CSL required? | Antidote |
|---|---|---|---|---|---|---|
| Brodifacoum | Possums, mice, rats, hedgehogs. | Single | Effective knockdown tool. | Second generation. Builds up in the environment. High risk of secondary poisoning. | No | Yes |
| Bromadiolone | Rats | Single | Effective knockdown tool and for ongoing control. | Builds up in the environment. Medium-to-high risk of secondary poisoning. | No | Yes |
| Cholecalciferol | Possums, rodents | Multi | Occurs naturally as Vitamin D3. Low risk of secondary poisoning. | Acute toxin so requires multiple feeds. More expensive than other options. | No | No |
| Coumateralyl | Rats, mice | Multi | Less potent than Brodifacoum, lower risk of secondary poisoning. | Not a knockdown tool. First generation, requires multiple feeds. | No | Yes |
| Diphacinone | Ferrets, rats, mice | Multi | Less potent than Brodifacoum, lower risk of secondary poisoning. Useful for ongoing control. | Not a knockdown tool. First generation, requires multiple feeds. | No | Yes |
| Pindone | Rats, rabbits, possums | Multi | Less potent than Brodifacoum, lower risk of secondary poisoning. Useful for ongoing control. | Not a knockdown tool. First generation, requires multiple feeds. | No | Yes |
| PAPP (Para-aminopropiophenone) | Stoats, feral cats | Single | Low risk of secondary poisoning. | Does not work on other species e.g. possums. | Yes |
Brodifacoum (aka Pestoff, Talon)
Effective on: possums, mice, rats, hedgehogs.
Second generation anticoagulant (blood thinning, leads to hemorrhage). This group of toxins are single feed pulsing toxins. Refresh baits every 4-6 weeks once stations are empty – this is important. If you do it earlier, it will be less cost effective because you are often feeding animals habituated to the food source and they already have a lethal dose.
One of the most widely-used rodenticides worldwide. Useful on private property and/or large parks and reserves. Effective knockdown tool. Second generation, prolonged use builds up in the environment and affects wildlife and other non-target species. Avoid using Brodifacoum in areas with livestock. Similar to Bromadiolone (see below).
Pestoff 20R with brodifacoum at 20 parts per million is one of the few toxins which has no bait shyness. Some brodifacoum products are 50ppm which can result in bait shyness if they are used incorrectly and constantly.
Where to buy: online and can be bought at your local hardware shop; may be provided by Councils, Landcare Groups.
No licence needed if contained in bait stations.
Antidote: Vitamin K1
Bromadiolone (aka Contrac, Rentokil Rid Rat)
Effective on rats.
Second generation anticoagulant like brodifacoum, but not as powerful.
Single feed, effective knockdown tool and for ongoing control. Medium-to-high risk of secondary poisoning. Second generation, prolonged use builds up in the environment and affects wildlife and stock. Suitable for parks and reserves in bait block form, contained in lockable bait stations.
No licence needed if contained in bait stations.
Where to buy: your local hardware store.
Antidote: Vitamin K3
Cholecalciferol (aka Vitamin D3, Pestoff Decal Possum Bait, Kiwi Care Gel, Feracol)
Effective on: possums, rodents.
Occurs naturally as Vitamin D3. Low risk of secondary poisoning. Causes cardiac arrest in target species.
Where to buy: online
No licence needed if contained in bait stations. Can be used on private property.
No antidote but less toxic than other options, so can have an increased risk of bait shyness.
Coumateralyl (aka Racumen, No Rats & Mice)
Effective on: rats, mice.
First generation anticoagulant, requires multiple feeds.
Not as potent as brodifacoum or other second generation anticoagulants.
Where to buy: can be bought at your local hardware shop.
Diphacinone (aka Ditrac, Ratabate, Liquatox, Pestoff (ferrets))
Effective on: ferrets, rats, less effective on mice (they often have to eat more than than 2x their own body weight to get a lethal dose)
First generation anticoagulant, multi-feed
Where to buy: online
Useful on private property, small and large parks and reserves depending on target species.
Not a knockdown tool, but lower risk than Brodifacoum of secondary poisoning.
Antidote: Vitamin K1
Pindone (aka Pindone Ag Tech Rabbit Pellets, Pindone Rabbit bait)
Effective on: rats, rabbits, possums (possums need 1-2kg and it takes 2-3 weeks to take effect provided bait is pulsed).
First generation anticoagulant, requires multiple feeds. Using pindone on rabbits needs experience as it is often hard to get them to feed out of stations. Good placement of stations where rabbits feed is essential.
Not a knockdown tool. Risk of secondary poisoning. Avoid using Pindone in areas with livestock.
Where to buy: farming suppliers.
Useful on private property and/or large parks and reserves depending on target species.
No licence required if contained in bait stations.
Antidote: Vitamin K2
PAPP (Para-aminopropiophenone) (aka PredaSTOP for Stoats)
Effective on: stoats, feral cats
Does not control other species.
Risk of secondary poisoning to non-target species.
Controlled Substance Licence required, landowners within 3km must be notified.
Antidote: methylene blue
1080 (aka Sodium monofluoroacetate) and cyanide (aka Sodium cyanide, Potassium cyanide, Feratox) and magtoxin (for rabbits) are acute poisons and require a Controlled Substance Licence (CSL).
For specific advice on predator control and permits in your region, contact your local council.
