Scientists have learnt new information on a type of underground bacteria that has the potential to enhance the productivity of Australian sugarcane crops, provided modern farming techniques are used.
The bacteria – called Pasteuria penetrans – is a natural parasite of root-knot nematodes, which are microscopic creatures that can damage the roots of sugarcane, resulting in lost production for growers and millers.
In new collaborative work at SRA’s Woodford pathology station, soil biologists have discovered that when there is a high concentration of Pasteuria in the root zone of sugarcane plants, the bacteria significantly reduce the population of root-knot nematodes, one of the most damaging pests of sugarcane.
Project leader Dr Graham Stirling said that root-knot nematode is widespread in Australian cane-growing regions, with the nematode a particular challenge because current sugarcane varieties are susceptible and there are no economically-effective control measures.
“Yield losses from plant-parasitic nematodes have been estimated to cost the Australian sugar industry more than $80 million per year in lost production,” Dr Stirling said.
The researchers said the message from their research was in line with SRA’s existing recommendations for improving soil health over the long term.
This included following practices such as adopting a controlled traffic and minimum tillage farming system, and maintaining good plant health through ensuring crops had optimised water and nutrients available to them.
Dr Stirling said that when soil is cultivated, this disrupted the interaction between Pasteuria and its nematode host.
“The only way to continually maintain high concentrations of endospores near the roots is to adopt a controlled traffic and minimum till farming system,” he said. “Some growers are already using best practice farming systems like this and – provided they are maintained for several sugarcane crop cycles – we would predict that Pasteuria will gradually increase to levels that will suppress root-knot nematode.”
The research was part of the SRA-funded project Regenerating a soil food web capable of improving soil health and reducing losses from soil-borne pests and pathogens of sugarcane, led by Dr Stirling.
The experiments involved collaboration with SRA Leader for Disease Traits, Dr Shamsul Bhuiyan, and Dr Jay Anderson from the University of Queensland.
Soil was collected from a field in Bundaberg where root-knot nematode was heavily-infested with Pasteuria and the results of a pot experiment with this soil showed that the parasite was having a major impact on root-knot nematode populations.