A corn earworm (Helicoverpa zea) larva feeding on a cotton plant
Debra Ferguson/Design Pics Editorial/Universal Images Group via Getty Images
Recent developments in Brazil have raised concerns about the emergence of hybrid strains of two major agricultural pests – the cotton bollworm and the corn earworm. These “megapests” have interbred, leading to the exchange of genes that confer resistance to pesticides. This genetic interchange poses a significant threat to crops like soya in Brazil and has the potential to impact global food security.
According to experts like Chris Jiggins from the University of Cambridge, the situation has the potential to escalate into a major agricultural crisis. Given that Brazil is a significant exporter of soya, with a large portion of it being genetically modified to resist pests, any decline in yields due to pest resistance could have far-reaching consequences on food prices and environmental sustainability.
The corn earworm, known scientifically as Helicoverpa zea, is a destructive pest that targets a wide range of plants, including corn, tomatoes, potatoes, cucumbers, and aubergines. While historically not a major threat to soya crops in Brazil, the introduction of the cotton bollworm, Helicoverpa armigera, in 2013 changed the landscape of pest management in the region.
Genetic analysis conducted by researchers like Jiggins has revealed that a significant number of Helicoverpa armigera moths in Brazil now possess genes that provide resistance to the Bt toxin, a common pesticide. Surprisingly, these resistance genes were acquired from Helicoverpa zea, showcasing the rapid evolution of pest populations in response to environmental pressures.
The transfer of resistance genes between these two pest species has raised alarms within the scientific community, with concerns about the potential spread of pesticide resistance and its implications for global agriculture. Angela McGaughran from the University of Waikato in New Zealand highlights the growing challenges posed by such “megapests” in an era of increased global connectivity and climate change.
To mitigate the spread of resistance, experts recommend adherence to resistance-management tactics, including the planting of non-Bt crops alongside genetically modified ones. While plant companies are developing new strains of Bt crops with multiple resistance genes, the need for sustainable pest management practices remains paramount.
As the agricultural sector grapples with the evolving threat of pest resistance, the case of hybrid megapests in Brazil serves as a stark reminder of the complex challenges facing global food production. With continued research and proactive measures, scientists and farmers aim to safeguard crop yields and ensure food security for future generations.
