Research Targets Rats

Landholders have welcomed the adapting of zinc phosphide to combat rats in agriculture.

The National Registration Authority (NRA) has granted an emergency use permit for Rattoff, an adaptation of the bait Mouseoff.

Animal Control Technologies commissioned chemists at DNR's Alan Fletcher Research Station to test the bait's suitability for rat control in cane areas. DNR collaborated on the project with BSES and Canegrowers, with support also coming from Aus Industry.

Zinc phosphide is already being used on rats in Hawaiian sugar cane areas. The DNR research is attempting to ensure the bait can also be used on rat species that cause serious damage to sugar crops in Queensland.

The research team studied the way the poison progressed through pest animals' systems and how to ensure it caused no harmful residues in the environment. Chemists are hopeful zinc phosphide will have the same minimal environmental and non-target impact in cane areas as it does in the grain areas of Queensland. Unlike most common rodenticides, zinc phosphide is lethal to mice in a number of hours rather than several days. This dramatically reduces the risk to native birds.

Ensuring zinc phosphide behaves similarly in poisoned rats is essential to limiting the risk of residue. There are also differences in behaviour between mice and rats that have made baiting rats a more complex exercise. These differences include neophobia, which is the fear of strange objects, and bait aversion, which happens when there is not enough bait to go around. Rats who only eat enough bait to become sick will often avoid baits from then on.