Agricultural pests that devour key food crops are advancing northwards in the US and becoming more widespread as the temperature heats up, new research warns. The corn earworm (Helicoverpa zea) is considered to be among the most common farm pests in the US, ravaging crops such as maize, cotton, soya and other vegetables. It spends winter underground and is not known to survive in states beyond a latitude of 40 degrees north (which runs from northern California through the midwest to New Jersey), but that is changing as soils warm and it spreads to new areas, according to research led by North Carolina State University.
The report follows research from the University of Washington in 2018 that found 2C (3.6F) of warming would boost the number and appetite of insects globally, causing them to destroy 50% more wheat and 30% more maize than they do now. Rising heat stress is already affecting yields, with harvests of staple crops in Europe down this year as a result of heatwaves and drought.
Pest invasions have serious implications for food security. “As the climate changes, the overwintering zones are likely to shift northward,” said the co-author Anders Huseth, an entomologist at North Carolina State University.