Mouse Control

The Hon. N.J. CENTOFANTI (Leader of the Opposition) (16:37): I move:

That this council—

1. Notes that mouse baits currently permitted for use in South Australian cropping areas are not as effective as the double-strength mouse bait which has previously been available under an emergency permit;

2. Notes that an effective formulation was previously available under an emergency permit, but an application for a minor use permit was turned down;

3. Expresses its disappointment that a bait that has been confirmed as safe and effective by CSIRO research is not readily available to South Australian farmers without annually seeking an emergency permit; and

4. Calls on the Malinauskas Labor government, in collaboration with its federal colleagues, to address the obstacles to the recent unsuccessful application for the minor use permit, and work with peak industry bodies to ensure that the most effective and affordable mouse control options are available to South Australian farmers as soon as possible, noting that time is of the essence.

South Australian farmers are among some of the most efficient in the world in the dryest state of the dryest continent on Earth. We are at the time when the usual autumn break occurs and when the seeding of the next season of broadacre crops starts in earnest. As we await the season break, many farmers in the state are starting to dry sow, hoping for coming rains. The business of growing the crops that feed a hungry planet carries significant agricultural risk as changes in rainfall, heatwaves, diseases and pests can decimate crops and impact farmers' incomes. It is a difficult job, even in the best of times.

One problem that is of great concern when seasonal conditions align is the explosion of mice populations or mouse plagues. Recent improvements in farming including the adoption of no-till grain production methods have given benefits in soil conservation but can also create suitable conditions for a carryover mouse population that can rapidly develop into a mouse plague under suitable conditions. When strychnine was no longer approved for mouse control, a new product, zinc phosphide 25, was approved and showed some promise. The 25 refers to the concentration in the bait: 25 grams of zinc phosphide per kilogram of grain.

Although it showed some promise, farmers' initial suspicions that control was suboptimal were confirmed with research by the CSIRO in a paper published in Pest Management Science showing that the 25-gram dose was not always lethal. This creates several problems, including the expense for farmers to bait multiple times, the fact that the mouse population can recover and expand in between suboptimal bait applications, and that affected mice that are not killed become bait averse, meaning they are unlikely to take bait a second time.

Subsequent research confirmed the need to ensure that all baited grain needed to be a lethal dose, and baiting with a double-strength preparation of zinc phosphide (or zinc phosphide 50) was shown to be very effective and very specific with no off-target damage. The CSIRO quotes GRDC pests manager Dr Leigh Nelson as saying that the three studies provide a solid body of evidence for the superior efficacy of the 50-gram zinc phosphide grain bait, which will give growers a more effective tool in managing mice to protect their crops.

As my federal colleague the member for Grey, Rowan Ramsey, has pointed out, during the 2021 mouse plague a temporary permit was granted for the use of the more effective formulation, zinc phosphide 50, which was renewed on an annual basis. This provided farmers with the confidence that there was an effective solution ready when required. The last permit to allow application of zinc phosphide 50 expired in November last year. However, despite the fact that CSIRO and GRDC research has confirmed the safety and effectiveness of this bait, the permit has not been renewed by the regulatory body, the APVMA.

Federal body Grain Producers Australia are the applicant for the permit, and they have reapplied to gain permission for Australian farmers to use the product, but there is no guarantee that they will be successful. The lack of efficacy over the single-strength bait, zinc phosphide 25, means that manufacturers and chemical suppliers lack confidence to stock the chemical. Lack of certainty about gaining approval of the effective double-strength bait means that suppliers are unable to make preparations for the coming grain season. This has created unacceptable uncertainty for South Australian grain growers and means that, should conditions arise for a mouse plague in the current season, it is highly likely our farmers will be left without effective control options.

A recent survey by Grain Producers South Australia shows strong support amongst South Australian farmers for the need and effectiveness of the double-strength bait. There has been some conjecture about why a permit has not been renewed, given the backing of research by Australia's pre-eminent research body and the grains industry research corporation. This conjecture is unhelpful. It has also been noted that the process for assessment and approval of control agents through the APVMA has been slow, with CropLife reporting that less than 79 per cent of assessments have been completed in the allotted time.

South Australian farmers need options, and they are needed now. Crops will be emerging and vulnerable to attack before long. Without correcting the status quo, our farmers and the entire state of South Australia will be worse off. It is imperative that we see leadership from the Malinauskas Labor government and from the primary industries minister on behalf of South Australian primary producers to ensure that our farmers are able to access the tools that they need to get on with the important job of growing crops, contributing to our state's economy and providing our state and nation with food into the future.

Whilst this issue may seem like a long way away from many of the folk here on North Terrace, I can absolutely guarantee that failure to address this need will leave our farmers vulnerable to avoidable loss and risk widespread crop loss and economic harm to the farming sector, damage to the state's economic viability and may well have an impact on food affordability into the future.

Debate adjourned on motion of Hon. I.K. Hunter.