Scientists warn of food crop mega-pest migrating to Asia Pacific

Australian scientists have warned that a recently discovered ‘mega-pest’ hybrid from South America could migrate to Asia Pacific and destroy food crops, thereby disrupting the global supply chain.

The scientists at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) confirmed the hybridisation of two prominent crop-destroying moths into a ‘new and improved’ mega-pest.

The hybrid is a cross between Helicoverpa armigera, also known as the cotton bollworm, which is prominent in Asia, Africa and Europe, and Helicoverpa zea, or corn earworm, which is native to South America. Helicoverpa armigera is responsible for damaging more than 100 types of crop including corn, tomato and soybean, costing billions of dollars annually.

CSIRO senior research scientist Dr Tom Walsh noted that the geographical movement of insect pests is a major emerging threat to global food security, adding that the mega-pest could reach Asia and Australia through natural movement or trade.

“We currently have a project to look at both these routes into Australia. With the amount of commodities coming from South America into Asia, I would be very surprised if there wasn’t a risk. The key finding from our work is that it is very hard to identify these individuals as they look like species that are already in Asia. The only way you can tell is by sequencing the whole genome,” said Walsh.​

CSIRO Biosecurity Risk Evaluation and Preparedness Programme research director Dr Paul De Barro said: “A hybrid such as this could go completely undetected should it invade another country. It is critical that we look beyond our own backyard to help fortify Australia’s defence and response to biosecurity threats.”​

The team studied a group of caterpillars and found that, in each case, every individual was a hybrid.

Walsh said of the discovery: “No two hybrids were the same, suggesting a ‘hybrid swarm’ where multiple versions of different hybrids can be present within one population. So we are at an early stage of the mixing event; the consequences of which are hard to predict.

“The major issue is that you no longer know what you are looking at. It used to be that you could say if it was one species or the other based on morphology, crop type and geography. This is not possible anymore with these two species in the New World.”​

The organisation stated it was important to study the pests to better prepare for sustainable, global management.