Scientific journals tend to use rather dry and constrained language. So when the title of an article describes a “mega-pest,” it’s time to be concerned.
Many gardeners and farmers are likely familiar with the corn earworm (Helicoverpa zea).The moth is native to the Americas and its larvae (earworms) devour corn. The cotton bollworm (Helicoverpa armigera) is a related species from Europe that affects a wide range of crops, including cotton, corn, tomatoes and soybeans, over several continents. That’s bad news but what’s worse, far worse, is that the two species have started to interbreed. This is occurring in the Americas, where the bollworm has become common. Some of the crosses are viable and there is evidence of “a wide range of genes” being passed between individuals of the two species, including genes for pesticide resistance, writes Anderson et al (2018). The bollworm is acquiring genes from the corn earworm and this may enable the bollworm to diversify its diet and range in North America. If/when this happens, conventional pesticides might not be able to control the pest because both the earworm and bollworms are known for quickly developing resistance to pesticides.
Source: Hybridization and gene flow in the mega-pest lineage of moth, Helicoverpa Craig J. Anderson, John G. Oakeshott, Wee Tek Tay, et al. April 2018. Proceedings of the National Academy of Sciences, 201718831
- Janet Wallace