17 August 2011
New possum toxin approved
The Animal Health Board (AHB) welcomes the registration of microencapsulated zinc phosphide (MZP) paste for the ground
control of possums. The toxin was approved by the Environmental Protection Authority (EPA) on 11 August 2011. The AHB -
along with Connovation Ltd and Lincoln University - supported Pest Tech Ltd's application to register MZP in New
Zealand.
The AHB undertakes extensive possum control each year to stop the spread of bovine tuberculosis (TB). Around 80 per
cent of this control work is carried out with ground set traps and toxins. Ground control is impractical in the
remaining 20 per cent of cases so aerially-applied sodium fluoroacetate (biodegradable 1080) is used. Unlike sodium
fluoroacetate, MZP is not registered for aerial application and can only be used in areas where ground control is
practical. Because it is a paste, it can only be used in certain bait stations.
Additional information about zinc phosphide
Zinc phosphide has been used in other countries as a vertebrate pest control tool since the 1940s. Possums appear to be
relatively susceptible, with a lethal dose of just 25 mg/kg. Death is caused through a combination of cardiac and
respiratory failure and normally occurs between three to five hours after the toxin has been ingested.
MZP poses a low secondary poisoning risk to scavenger species and dogs. It does not bioaccumulate and is considered a
humane toxin. There is no antidote to MZP, with treatment being mainly symptomatic and supportive. Strict conditions
have been placed on the use of the toxin to protect applicators, bystanders and the environment.
- ends -