PNAS: Soil temperature can predict the spread of pests in crops

A new study from North Carolina State University shows that soil temperature can be used to effectively monitor and predict the spread of corn earworm (Helicoverpa zea), an important pest that seriously harms corn, cotton, soybeans, peppers, tomatoes and other vegetable crops

The researchers combined historical soil temperature data with long-term surveillance data for corn earworms and information on how this pest survives in cold conditions in a laboratory environment to better understand "overwintering success," or how this pest survives underground during the colder winter months

The researchers say greater overwintering success rates can expand areas where pests live and thrive because pests can migrate long distances

Douglas Lawton, a former postdoctoral fellow at North Carolina State University, said: "There is a preconceived notion that pests can barely overwinter

The study showed that a latitude of 40 degrees is not the optimal watershed for a successful wintering, so much so that the researchers designed their own map — covering three different datasets — to show three related geographic regions: the "southern mountains" where pests can survive in winter, the "northern boundary" area where pests generally cannot survive in winter, and a "transition zone" between northern and southern regions where pests may or may not survive

"These fields are biologically relevant and supported

The researchers used these three regions to show historical trends in corn earworms, and then used a model to predict the spread of corn earworms to the end of the century

"As the climate changes, the wintering zone may move north," said

The data shows that the winter in Minnesota is harsh, and from 1950 to 2021, corn earworms did not successfully overwinter

"It's like a canary in a coal mine, a natural enemy of agricultural pests," Houthi said

"Now we want to come up with a better prediction tool for this pest, as well as a risk prediction model, in order to give growers better information

essay

Pest population dynamics are related to a continental overwintering gradient