Deterring possum browsing with a repellent spray

2 minute read

Possum close up

Yates Australia developed Yates Possum Repellent Spray to discourage possums from causing damage to urban parks and gardens. The product is based on research from the University of Melbourne.

Key points

  • Yates Possum Repellent Spray deters possum browsing, or eating plant leaves, shoots and fruits.
  • Possums damage ornamental and fruiting plants. But few options exist for controlling the animals, which are protected by law in Australia.
  • Yates Australia licensed the intellectual property from the University of Melbourne.

The outcome

Yates Possum Repellent Spray deters possums from eating plants. It was developed by Yates Australia using research from the University of Melbourne.

The need

Common brushtail possums (Trichosurus vulpecula) and common ringtail possums (Pseudocheirus peregrinus) damage urban parks and gardens in Australia. Both species are native to Australia and are protected by state and federal laws. In the state of Victoria, possums are protected by the Wildlife Act 1975. It is illegal to capture or kill possums without a permit.

Several proprietary possum deterrents are commercially available. Other products – such as fish sauce, animal-based fertilisers or garlic – are also used. However, a study of 14 products commonly used to deter possum browsing found that none was completely effective.

Effective, humane and non-lethal methods are needed to reduce possum browsing.

The research

Biologist Professor Lynne Selwood began investigating methods for deterring possum browsing in the 1980s. Possum deterrents rely on smell, taste or texture to discourage the animals from eating plants.

As a gardener, Professor Selwood wanted to discourage possums from browsing in her backyard. Over several decades, she tested various products, focussing on natural substances. She found that applying pyrethrin, a plant-derived insecticide, to plants could deter possums from browsing. However, pyrethrin degrades in sunlight. It is also washed away by rain.

Professor Selwood combined the pyrethrin with diatomaceous earth and mineral oil. Diatomaceous earth is a powder made from the fossils of diatoms – microalgae with a cell wall made from silica. It is used in the garden as an insecticide and in potting soil. This combination of materials helped the pyrethrin solution stick to leaves. It may have also protected the pyrethrin from sunlight.

Professor Selwood tested the solution in her own garden over 20 years. She also tested it in 10–12 other gardens over three years.

Technology development history

Professor Selwood patented the possum deterrent solution in Australia and in New Zealand. She donated these patents to the University of Melbourne in 2013.

Yates Australia licensed the intellectual property from the University in 2014. The garden supplies company is a division of DuluxGroup (Australia) Pty Ltd.

Yates worked with Professor Selwood to improve the deterrent solution. The company tested its efficacy in a commercial nursery. The solution was effective in reducing possum browsing for up to seven days after application.

Yates registered the product with the Australian Pesticides and Veterinary Medicines Authority in 2018. Yates Possum Repellent Spray was introduced to the Australian market in 2019.

Partner

Yates Australia

Patents

AU2015203790, filed on 7 July 2015 (‘Methods for controlling pest animals’)

AU2012203727, filed on 22 June 2012 (‘Methods for controlling pest animals’)

NZ600852, filed 22 June 2012 (‘Methods for controlling pest animals’)

People

Professor Lynne Selwood

Banner picture: Ken Mercer

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