Biological control of possums – introduction

Possums are one of New Zealand's biggest pests. Currently they are controlled by poisoning and trapping, but this is expensive and ongoing. Biological control has the potential to provide novel ways to control possums, and combined with conventional control methods, may offer more sustainable solutions.

Why possums are a problem

Possums are a pest in New Zealand. They eat the native trees, birds and invertebrates, and destroy ecosystems. They can also spread tuberculosis, which has a huge financial impact on the dairy and beef industries.

Current methods of control

Possums are currently controlled through trapping and poisoning (using mainly 1080). These methods are very costly and in the case of poisoning, not specific to possums.

What is biological control?

Biocontrol methods are:

• sustainable, having ongoing, permanent effects
• specific to the species being controlled.

Methods of biocontrol

Scientists in New Zealand explored several biocontrol methods for reducing possum numbers. These included using toxins or vaccines against possum fertility. Further information on two examples are in the articles: Hormone-toxins to reduce possum fertility and Vaccines to reduce possum fertility.

There are a number of ways biocontrol agents, like toxins or vaccines, can be delivered to possums. We need to consider the advantages and disadvantages of each method of delivery before we decide which option to use. Find out more in the article, Delivering biocontrol agents to possums.

This article, provides explanations of key terms and definitions in possum biocontrol.