‘The worst rat infestation I’ve seen in 30 years’: why?

A rat infestation has destroyed many of Australia's sugarcane crops.
'The worst rat infestation I've seen in 30 years': Why?

A “perfect storm” of conditions has led to masses of rats invading some of Australia’s biggest sugarcane fields.

The infestation has taken place in northern Queensland, and has forced growers to take significant measures to protect their crops from total destruction.

First, the basics

Sugarcane is a plant that produces raw and refined sugar, and can be used to ferment drinks, such as rum.

About 95% of sugarcane is grown in Queensland.

Australia is the second largest raw sugar exporter in the world, with Asian countries the most important trade partners.

How’s this happened?

Sugarcane crops were being finalised for harvest just before Christmas, meaning they were close to being gathered from the fields.

However, two consecutive mild wet seasons allowed the local rat population to grow. This is because rain usually kills local rats through drownings or exposure to the cold. With less rainfall, more rats survived the wet seasons.

Due to this, growers had an unusually high amount of both sugarcane and rats in the area, making the sugarcane particularly vulnerable to pests. The rats have been feeding on sugarcane to gather fibre in their diet, causing it to rot.

The damage

Sugarcane wrecked by rats. Photo: Supplied.

The impact

Lawrence Di Bella, the manager of Herbert Cane Productivity Services on the north Queensland coast, told TDA the rat infestation was the “worst” he’s seen in 30 years.

He estimates the rats have dismantled up to 400,000 tonnes of sugarcane in the Herbert Rivers district of Queensland.

How’s it being stopped?

Growers have received permits from the Queensland Government to cull the rats found in the sugarcane fields. The permit had to be granted because the rats are a native species.

Rat baiting systems are being distributed on the ground and from drones or helicopters. Di Bella said the programs used are designed to cull rats but protect other species from harm.

What’s next?

Di Bella said that heavy rainfall, which has been recently felt in parts of Queensland but not in his area, would help reduce rat populations.

This would support a healthy local rat population, which would then ease pressure on sugarcane being grown in the area.

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