E-Paper
Scientists develop eco-friendly spray to combat chickpea pest Helicoverpa armigera
Responsible for global chickpea losses of around USD 330 million annually, the pest not only threatens chickpeas but also infests cotton, pigeonpea, maize, tomato, and other crops
In a significant breakthrough for the agriculture sector, scientist Vandana Ghormade and her team have from Agharkar Research Institute unveiled an innovative, eco-friendly solution to tackle Helicoverpa armigera, commonly known as the gram pod borer, a pest which causes severe damage to chickpea crop.
Responsible for global chickpea losses of around USD 330 million annually, the pest not only threatens chickpeas but also infests cotton, pigeonpea, maize, tomato, and other crops. India, the world leader in chickpea production with nearly nine million tonnes annually, faces significant losses due to Helicoverpa armigera. Traditional chemical pesticides have long been used to control pests, but over time, the insects have developed resistance, including to Bt-containing genetically modified plants, while excessive chemical use has caused environmental harm.
Ghormade’s team focused on RNA interference (RNAi), a method that silences essential genes in pests by blocking and destroying their mRNA. While RNAi has enormous potential for its precision and non-toxic nature, its practical use in agriculture has been limited due to challenges in delivering stable RNA molecules that can survive the insect gut environment.
To overcome this, the researchers developed a topical RNAi spray using chitosan-based nanoparticles as carriers for double-stranded RNA (dsRNA). These nanoparticles protect the RNA from degradation, enhance its uptake by the insect gut, and allow for effective gene dsRNA was carefully designed using bioinformatics to target two crucial H. armigera genes, juvenile hormone methyltransferase and acetylcholine esterase, without affecting non-target insects.
Ghormade said, “Laboratory tests revealed remarkable results, like even low doses of the nanoparticle-dsRNA complexes triggered complete silencing of the targeted genes in the larvae, leading to a significant drop in enzyme activity and 100% mortality. Importantly, the spray was non-toxic to other insects such as Drosophila and Spodoptera, and showed no cytotoxicity in vitro”.
Further, she said the innovation was further tested in chickpea fields at Agricultural College, MPKV, Pune, with the help of students Henry Kolge and Karthiki Kadam.
The results were impressive: “Two low-dose applications of the nano-RNAi spray effectively protected crops from pod borer infestation, providing crop protection comparable to chemical sprays, while ensuring high yields and minimal pod damage. The spray also showed no signs of phytotoxicity, reinforcing its safety for plants.”
“Nanomediated delivery of RNAi is a specific approach to address the issue of insect resistance,” said Ghormade. “Under the DST-SERB-sponsored project, we developed a nano-RNAi spray targeting Helicoverpa armigera. The laboratory tests confirmed its insect efficacy and safety for non-target species. Field applications at low concentrations were equally effective. Further multi-location trials and ecological safety studies could enhance the potential of this technology for large-scale agriculture.”
The pioneering work opens the door to a new generation of bioinsecticides that are not only highly specific and environmentally safe but also capable of overcoming the growing problem of pest resistance.
