According to new research, agricultural pests are advancing northwards in the US, becoming more widespread as the climate warms up. The corn earworm (Helicoverpa zea) is considered to be among the most common farm pests in the US, affecting crops such as maize, cotton, soya and other vegetables. It is not known to survive 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 effects of insects globally, causing them to destroy 50% more wheat and 30 percent more maize than they do now.
Increased 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.
Over the coming decades the model illustrates that this insect could expand its overwintering range into the US maize belt in Ohio, Indiana, Illinois, Missouri and Iowa. In Minnesota, for example, no corn earworms have successfully survived its harsh winters, but the models suggest the whole state will be in the transitional zone by the end of the century.