Enviro-friendly spray targets crop killer

Enviro-friendly spray targets crop killer

Enviro-friendly spray targets crop killer

An environmentally friendly spray targeting one of the world’s most damaging agricultural pests has been created by Australian scientists.

Heralded as a crop production game-changer, the technology is chemical free and has been developed by University of Queensland researchers over the past decade.

Research team leader Neena Mitter said it was a breakthrough for crop protection because it was effective against silverleaf whitefly, a small insect responsible for the loss of billions of dollars in crops around the world.

The whitefly attacks more than 500 plant species including cotton, pulses, chilli, capsicum, and many other vegetable crops.

“We silence the genes of whitefly using their own RNA,” Professor Mitter told AAP.

RNA is a molecule present in all living cells that has structural similarities to DNA.

The scientists sprayed the RNA on the plant so when the insect feeds it kills them. The RNA is specific to the targeted species.

Prof Mitter said the research, published in the scientific journal Nature Plants on Tuesday, had worked out how to silence genes in the pest and is carried in an environmentally friendly clay called BioClay.

“If we want to kill whiteflies we make the RNA specific to whitefly, if we want to kill another insect we make the RNA specific to that,” she said.

“The insect lays eggs on the underside of the leaves and the nymphs and adults suck the sap from the plant resulting in reduced yields.

“The uniqueness of our technology is partnering the RNA with clay particles … which makes it possible for the RNA to last longer on the plants so it does not get washed off by rain, it sticks to the leaves and slowly releases the RNA.

“The world wants to move away from chemical pesticides and this is one of the tools.”

To identify suitable gene targets, PhD candidate Ritesh Jain went through the global database of genome sequences.

“Initially, we had to screen hundreds of genes specific to SLW (silverleaf whitefly) to see which ones would affect their growth,” Mr Jain said.

“Importantly, the RNA proved harmless when fed to other insects, such as stingless bees and aphids.”

Susan Maas from the Cotton Research and Development Corporation said silverleaf whitefly was a major pest for cotton across the globe due to its ability to contaminate and downgrade lint quality.

She said the technology was a game-changer for the cotton industry.

“It is highly specific to the target pest, in this case it is whitefly, so that any impact on beneficial crop insects is negligible,” Ms Maas said.

“It also has a very low impact on the environment with no residues remaining after application.

“BioClay sets up a framework for the potential development of other targeted pest specific products in the future, tackling different pest control challenges in a highly focused, environmentally safe way.”

Cotton Australia Chief Executive Adam Kay said growers were also involved in the project and shared their on farm experience.

“This development is an exciting breakthrough for cotton farmers and all farmers impacted by whitefly.”

Liv Casben
(Australian Associated Press)

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