A new study from N.C. State University shows how the temperature of soil could help farmers predict the spread of certain common crop pests.
The study's focus was on corn earworms, a caterpillar that's found on crops like cotton, corn and soybeans. Corn earworms also fly when they become adults.
Understanding overwintering success
To start the process, researchers looked at the effects climate change had on common crop pests surviving winter temperatures up north.
Next, they combined historical soil temperature data with long-term monitoring of the corn earworm's "overwintering success."
Anders Huseth, an assistant professor of Entomology at N.C. State, said overwintering success is how well the insect can survive in cold conditions underground.
The corn earworm overwinters during a phase called diapause. During this phase, it’s between being a caterpillar and an adult.
Researchers call them pupas.
“This insect will burrow into the soil waiting out until favorable spring conditions and host plants are available for its caterpillars,” said Huseth, who’s also a co-author on the study published in Proceedings of the National Academy of Sciences.
The three overwintering zones
The researchers used three zones of different soil temperatures to show historical trends for the corn earworm’s overwintering success and then used a model to make predictions about pest spread through 2099.
Douglas Lawton, a data scientist at Raleigh-based biotech company AgBiome and another co-author of the study, said the three zones were to show three different geographical areas.
“A Southern Range where pests survive over the winter months, a Northern Limits area where pests are generally unable to survive during winter months, and a Transitional Zone in between the northern and southern areas where pests may or may not survive over the winter,” said Lawton.
Both Lawton and Huseth concluded that as the climate changes, the overwintering zones are likely to shift northward.
With the large amount of data they collected, the researchers believed this could help more than just North Carolina farmers. Farmers along the east coast may also benefit.
“We're able to provide insight about risk for infestation and risk for infestation over multiple years,” said Huseth. “That gives growers an idea about what they need to be concerned with in any given season.”
The study also showed that by predicting pest spread sooner, it could help farmers reduce the financial and environmental impacts of pesticide use.
