Newly detected ‘hybrid swarm’ a major concern for global agriculture

By Leslie Gladstone

Australian scientists recently published a paper containing evidence for a hybridization of some of the world’s worst pest species. A hybrid of the corn earworm and the cotton bollworm was confirmed to have been discovered in Brazil according to experts.

Before the hybridization event, the two species had been geographically isolated. The cotton bollworm was widespread in Africa, Asia and Europe while the corn earworm was native to the Americas.

This discovery poses a major threat to agriculture globally. The cotton bollworm is known to infest over 100 crops, including corn, cotton, tomato and soybean. Additionally, the bollworm benefits from high mobility and pesticide resistance. Scientists estimate that 65 percent of the USA’s agricultural output produced in South America is currently at risk.

Scientists conducting the study for Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) used genome sequencing technology to confirm the presence of the hybrid. CSIRO scientist Dr. Tom Walsh announced that among the caterpillars studied, “No two hybrids were the same suggesting a ‘hybrid swarm’ where multiple versions of different hybrids can be present within one population.”

The Australian National Science Agency is on high alert and has said that continued research remains a top priority due to the hybrid swarm’s wide-ranging implications. Scientists emphasized the importance of the study of pests for early detection and sustainable long-term management. Dr. Paul de Barro serves as Research Director for CSIRO’s Biosecurity team. “It is critical that we look beyond our own backyard to help fortify Australia’s biosecurity threats.”


CSIRO Australia. (2018, April 6). Hybrid swarm in global mega-pest. ScienceDaily. Retrieved April 14, 2018 from