Now, Douglas Lawton from North Carolina State University and colleagues have developed models demonstrating that climate change may expand the range of a migratory agricultural pest, the corn earworm, Helicoverpa zea (Boddie). H. zea pupae can overwinter underground in North America and the winter soil temperature is critical for overwintering survival. Lawton and the team combined historical soil temperature data, long-term corn earworm monitoring data, and laboratory-based low-temperature survival threshold data to estimate the impact of climate change on pests’ distributions and population dynamics. The team suggests that over the past 40 years, temperature changes have expanded the soil temperature suitability for H. zea. The southern range of overwintering zone areas has been expanded by 3% since 1981 and is projected to increase twofold by 2099, indicating increases in the overwintering survival success in more northern latitudes.
Modelling insect population dynamics is essential for sustainable crop protection. Lawton and the team modelled H. zea annual and seasonal population dynamics based on overwintering suitability zones using four decades of soil temperature data. The expanded range of H. zea may cause increased pesticide use and yield loss in northern maize production regions in North America. This study showcases the value of combining large spatiotemporal datasets to predict species distributions and demonstrates that effective monitoring at the continental scale for migratory pest species may maximize the pest management effects.
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