Cotton pests are targeted using an environmentally friendly insecticide

Australian scientists Ritesh Jain (L) and Professor Neena Mitter say tests using BioClayTM on cotton plants are harmless to other insects including the stingless bee (Tetragonula hockingsi) and aphid (Myzus persicae). Credit: University of Queensland

Silverleaf whitefly, one of cotton’s most destructive agricultural pests, has been killed by experts at The University of Queensland with an environmentally friendly spray.

CRDC, Hort Innovation, and Nufarm Ltd. have all contributed to the development of Queensland Alliance for Agriculture and Food Innovation (QAAFI) and the Australian Institute of Bioengineering and Nanotechnology (AIBN) over the past decade, which has resulted in BioClay, a safe and sustainable alternative to chemical pesticides.

Because it was effective against whitefly (Bemisia tabaci), a microscopic bug that causes billions of dollars in crop losses throughout the world, the research team’s leader Professor Neena Mitter stated it was a game changer for crop security.

More than 500 plant species are attacked by the invasive silverleaf whitefly (SLW), including cotton, legumes, chilli, capsicum and many other vegetable crops, according to Professor Mitter.

A reduction in yields can be caused by the insect’s eggs being laid on the underside of the leaves, as well as its nymphs and adults sucking sap from the plant.

Whiteflies can also spread a wide variety of pathogens, putting healthy crops at risk.

Due to the bug’s propensity to swiftly acquire resistance to typical chemical pesticides, control of the pest has proven difficult.

Degradable clay particles that carry double-stranded RNA are used in the BioClay spray, which protects the plant without modifying its DNA.

For the first time, Professor Mitter stated, the BioClay platform has been utilised to target sap sucking insects.

dsRNA kills whiteflies by targeting genes that are vital to their survival when they absorb it while feeding on the sap.

Not only will RNA transform agriculture by defending plants from viruses, fungus and insect pests using COVID-19 vaccines, she said.

Ritesh Jain, a Ph.D. student looking for potential gene targets, combed through the world’s genome sequence database.

First, “we had to analyse hundreds of genes particular to SLW,” Mr. Jain said. We wanted to identify which ones affected their growth.”

It’s important to note that the dsRNA was safe for other insects, including stingless bees and aphids, when fed to them.

Susan Maas, CRDC’s Senior R&D Manager, says SLW is a major pest of cotton worldwide because of its potential to contaminate and degrade lint quality.

Australia’s reputation for producing clean, high-quality cotton in a safe and environmentally sustainable manner will benefit from this new technology, according to Ms. Maas.

Research and development manager Dr. Vino Rajandran of Hort Innovation said the spray might be another biosecurity tool for the industry. According to Dr. Rajandran, “It has the potential to save growers time and money and is an excellent example of industry levy investment in action.”

Whitefly BioClay will now be tested in real-world production systems by researchers working with industrial partner Nufarm Ltd.

One of the primary scientists at Nufarm, Mike Pointon, said the company was thrilled to be working with “world leading experts to develop cutting-edge technologies that deliver new, alternative control options to farmers.” — Mike Pointon

Nature Plants has published the findings.

Further information: Ritesh G. Jain et al, Foliar application of clay-delivered RNA interference for whitefly control, Nature Plants (2022). DOI: 10.1038/s41477-022-01152-8

Journal information: Nature Plants

Source: University of Queensland