Why target possums?
We all want our native plants and wildlife to thrive. However, possums pose one of the biggest threats to our ecosystem by eating birds, birds’ eggs, and trees. They also compete with native wildlife for food and spread diseases such as bovine tuberculosis.
Possums are nocturnal and mostly live in forests, along forest borders and on bush blocks, occupying holes in tree trunks that might otherwise house nesting birds. (For more details, read our Possum Facts.) However if you see them often during the day this generally means there are very high possum numbers.
Why use baits?
Note: This information is intended as an overview. It’s important to get region-specific advice from your council, landcare group or DOC, as well as obtaining any necessary permits.
All tools have their advantages, limitations and risks. Toxic baits can be a useful ‘knockdown’ tool for controlling dense populations over large areas, saving time, money and resources. However, baits can also pose a risk to dogs, livestock, and other non-target species.
Bait stations should be placed away from public tracks and out of reach of children and pets (dogs are particularly sensitive to brodifacoum and pindone – see below). Stations should always be clearly signposted in public areas with information on which bait(s) are being used, the associated risks, and emergency contact numbers. Any neighbouring properties should be notified that toxic baits are in use, and baits should be kept well away from livestock, children and dogs.
Prolonged use of toxic baits also affects the environment. For this reason, it is recommended that you alternate baiting with trapping. Overuse of baits can also lead to possums becoming bait shy with some types of toxins (i.e. they avoid eating the bait).
- All toxins should be contained in bait stations. Commonly-used stations for possums include Philproof, Kilmore and Sentry. See our guide on where to buy equipment.
- Bait stations must be placed out of reach of livestock, pets and other non-target species, and clearly signposted. At least 1m above the ground is recommended if weka, kiwi or other ground-dwelling native birds are in the area.
- Placement will depend on your target area, accessibility, and proximity to non-target species. Generally, bait stations should be about 100-150m apart for possums, with at least 1-2 stations per hectare.
- Keep a record of your bait stations as well as which baits you’ve used and when. (Trap.nz is a free website and app that allows you to record and monitor your traps and stations.)
Toxins are poisons and safe handling is essential.
- Always follow the manufacturer’s instructions, product label and Safety Data Sheet (comes with each product and often available to print out through the manufacturer or retailer’s website, e.g. Pestoff) – to avoid buildup or poisoning it’s crucial to use as per the label.
- Wear protective gear (e.g. strong rubber or leather gloves, face mask) and keep toxins contained in bait stations.
- Most poisons have antidotes, but they must be administered by a vet/doctor in the early stages. If poisoning is suspected, contact a vet/doctor immediately or call the National Poisons Centre on 0800 764 766 (0800 POISON).
- Remove old bait before refilling stations and avoid ground spillage.
- Remove all old or unused bait – dispose of it responsibly offsite (read product labels for advice).
- In populated areas and for backyards, consider trapping (see our best practice for possum traps).
- Ensure livestock, dogs and children cannot access the bait stations (always secure them well if on fences and facing away from paddocks; place at heights where they cannot access the bait). If using paper sachets instead of bait stations, don’t place these on paddock fence posts.
Which baits to use and when
Below is a summary of toxic baits commonly used for controlling possums. Most (brodifacoum, cholecalciferol, pindone, diphacinone + cholecalciferol) don’t require a Controlled Substance Licence (CSL) as long as they are contained in bait stations and handled according to the manufacturer’s guidelines. If you’re new to bait stations and or using toxins, read our introduction to bait stations and find an experienced person to work alongside until you feel confident doing the work yourself.
Note: To avoid bait shyness and toxins building up in the environment, it’s best to alternate different baits over time. Some possum control experts recommend using Feratox or Double Tap as the initial control tool, and then switching to brodifacoum, cholecalciferol, pindone and Double Tap once possum numbers are reduced.
Possums don’t like wet weather, so targeting them during fine weather (particularly in the colder months) tends to work best. The best time of the year for possum control is winter, when natural food supplies are at their lowest and possums are hungry and more likely to take alternate foods. Just before spring is also a good time because reducing predators will help protect nesting birds in the area.
For signs of possums, look out for scratches on trees, damaged fruit, foot tracks and faeces. Possums respond to visual cues so, to attract possums to a bait station, use a lure such as white flour mixed with scented spices, e.g. cinnamon. Place the lure outside the station or on the tree trunk and scuff up the surrounding area to create interest.
We have written an at-a-glance summary of baits for controlling possums — it includes details on each bait and pulsing advice.
Brodifacoum (aka Pestoff )
Brodifacoum can be useful for controlling low numbers of possums and is suitable for use on private property. Also effective on rats. Pellets are dyed blue. It’s a second-generation toxin with a high risk of secondary poisoning. Avoid using brodifacoum in areas with livestock. It’s a good idea to alternate brodifacoum on an annual basis to reduce buildup in the environment. Brodifacoum Possum Bait should not be used alone as the initial control method where high possum densities occur (see cholecalciferol below).
No CSL required.
Antidote: Vitamin K1. Warning signs need to remain out for 12 months after bait has been removed.
Where to buy: Your local hardware store or farm supply stores, in cereal or block form.
How to use: Pulse four times a year (August, November, January and April). Fill bait stations on day 1. Replace any bait eaten initially over the next 6-8 days. Remove any uneaten, mouldy or damaged bait before refilling stations. Dispose of any old or unused bait according to the product label. Repeat baiting only after 4-5 weeks have passed so that lethally poisoned animals die and do not keep taking bait. This also allows less dominant animals to gain the confidence to eat out of stations. In most situations, 4-5 applications per year will be enough to reduce possum densities and maintain them year-round at low numbers. Follow the manufacturer’s instructions on amounts of bait to use per bait station.
Pindone (aka Pindone Pellets)
Pindone is a first generation (developed before 1970, less potent) multi-feed. Not a knockdown tool for high-density areas, but can control populations to keep numbers low. Also effective on rats. Possums need to consume 1-2kg and it can take a few weeks to take effect. Suitable for private property but avoid in areas with livestock. Baits are dyed green. No CSL required.
Antidote: Vitamin K2. Warning signs should remain until at least 3 months after baits have been removed.
Where to buy: Farming supply stores.
How to use: August, November, January and April. Fill bait stations on day 1, then refill on days 3 and 5. Refill again on day 14. (If less than half the bait is still there when you refill on day 14, consider refilling on day 17 as well until signs that rodent or possum activity has ceased). Follow the manufacturer’s instructions on amounts of bait to use per bait station. This is important because low and high numbers of rats and possums require different volumes in bait stations. Remove bait at the end of week 4 and dispose of as per the product label.
Cholecalciferol (aka Vitamin D3, Feracol, Pestoff Decal Possum Bait)
Cholecalciferol is a multi-feed bait with a lower risk to non-target species than brodifacoum. It can be more expensive than other bait options and there is no antidote (although treatment is possible if poisoning is detected early). Warning signs must remain for at least 3 months after baits have been removed. For best results, pre-feed for one week before each toxin application to avoid bait shyness. No CSL required. To find out more, contact the Biosecurity team of your local regional council.
Where to buy: From the manufacturers (e.g. Connovation) and predator control supply companies (e.g. Pestoff).
How to use: Pre-feed for 1-2 weeks with Pestoff Pestfeed bait (if using Decal possum bait), or Ferafeed (if using Feracol). Replace with toxic bait at the end of the pre-feeding period. Refill bait stations with toxic bait approximately 3 days later, and again after 7 days if bait take has continued. Replace eaten toxic baits only once or twice before pre-feeding again if ongoing control is required. Remove any uneaten bait after two weeks and dispose of as per manufacturer’s label. Follow the manufacturer’s instructions on amounts of bait to use per bait station. Where possible, an application of Brodifacoum Possum Baits between applications of Cholecalciferol Possum Bait may achieve very low possum densities. Anticoagulant baits act as a synergist (increased effectiveness) when applied in conjunction with cholecalciferol bait.
Feratox is an encapsulated cyanide and requires a CSL. Useful for controlling medium-to-high possum density and an effective knockdown tool before using other toxins to maintain low possum numbers. It is generally a low risk to non-target species when used appropriately. Not designed for controlling rats. For best results, pre-feed with Ferafeed for one week before each toxin application to avoid bait shyness. Warning signs should remain until at least 2 months after baits have been removed
Antidote: amyl nitrate [AF12] capsules
Where to buy: From the manufacturer (Connovation).
How to use: Following prefeeding for 3-10 nights, place 2-5 pellets with 5-20 g of Ferafeed non-toxic pellets or paste in each bait station. Revisit bait stations after 4-5 days and where baits are taken, replenish with more toxic bait. After a further 5 days remove all baits and pre-feed to prevent any surviving possums becoming bait shy. Dispose of bait as per manufacturer’s label.
Diphacinone + cholecalciferol (aka Double Tap)
When cholecalciferol is combined with diphacinone, the anti-coagulant (blood-thinning) properties of diphacinone are enhanced. That means it has a similar efficacy to brodifacoum, but without the residue issues. Suitable for most densities of possums. Warning signs must remain until at least 2 months after baits have been removed. No CSL required. To find out more, contact the Biosecurity team of your local regional council.
Where to buy: From the manufacturer (Connovation).
How to use: Fill bait stations on day 1 Check and refill where necessary after 6-10 days and continue use for 2-2.5 months to manage the control of all resident and immigrant possums and rats. Follow the manufacturer’s instructions on amounts of bait to use per bait station. Remove any uneaten bait after four weeks and dispose of as per manufacturer’s label.
- Pest Animal Control Guidelines from Auckland Council (PDF).
- Northland Pest Control Guidelines from NZ Landcare Trust (PDF).
- Brodifacoum: its use for possum and rodent control in forests and farmland from National Pest Control Agencies (PDF).
- Cholecalciferol: its use for possum and rodent control from National Pest Control Agencies (PDF)
- Private landowner’s guide to possum control from National Pest Control Agencies (PDF).