Aerial bid to control rats in sugarcane

CANEGROWERS has secured a minor use permit from the Australian Pesticides and Veterinary Medicine Authority (APVMA) for the aerial baiting of rats in response to a population boom in two key cane-growing areas that looks set to cost the industry millions of dollars.

Areas of sugarcane which had lodged (fallen over) in the Mackay and Herbert River districts, coupled with weed-growth promoted by unseasonal winter rain, created the perfect conditions for two species of native rat to thrive during 2016.

“While growers can bait for these rats in sugarcane, the conditions meant they couldn’t get into their paddocks to place baits by hand, leaving the rats to cause significant damage,” CANEGROWERS Environment and Sustainability Manager Matt Kealley said.

“Rats gnaw the cane stalks off at the base, the cane then deteriorates and the sugar content is compromised. In 2016 the cost of rat damage in these two districts was more than $6 million.

“With around 500,000 tonnes of big standover cane left behind after rain stopped the harvest, the rats are still having a feast and that’s going to impact on the 2017 season.”

CANEGROWERS worked closely with Animal Control Technologies (manufacturer of the approved bait Rattoff®), chemical registration consultancy DeGroot Technical Services, Herbert Cane Productivity Services Limited (HCPSL) and Mackay Area Productivity Services (MAPS) to progress a Minor Use Permit through the APVMA. 

The APVMA has now approved a permit to enable Rattoff® application to lodged sugarcane crops via helicopter or UAV.  

“This permit covers up to 10,000 hectares in the Herbert and Mackay districts for 2017,” Mr Kealley said. “It will be very helpful as growers try to control the current infestation.”

Mr Kealley said measures would be taken to ensure the baiting program did not impact on non-target wildlife.

“We had to demonstrate to the APVMA that distributing Rattoff® sachets by air would not poison other species,” he said. “We showed them what lodged cane looks like and explained that the dull-coloured sachets would fall through the stalks to the ground making them less visible and less accessible to birds but available to the rats.

“Birds of prey have little risk of being poisoned with Rattoff® and its formulation minimises risks to the environment.”

Rats don’t only cause problems in the cane field.

“Rat damage also causes cane processing issues,” Mr Kealley said. “In the Victoria and Macknade mills in the Herbert River districts, rat-damaged high-fibre cane caused the mills to choke, impacting on the efficiency of the mill.

“CANEGROWERS has also been made aware that cane deterioration from rat damage causes elevated levels of dextran in cane juice and this can cause processing issues at pan stage, making the production of high quality sugar more demanding and expensive.”

MAPS and HCPSL will assist growers to bait for rats in their respective regions under the conditions of the permit.