By Blake Jackson
Researchers at Penn State’s College of Agricultural Sciences have found that cover crop selection can influence how future crops defend themselves against insect pests. The study, published in Basic and Applied Ecology, examined how different cover crops affect plant chemistry and interactions with beneficial insects.
The research showed that corn grown in soil previously planted with pea cover crops released higher amounts of indole, a chemical that helps neighboring plants activate defenses against insect attacks. However, those same plants contained lower levels of benzoxazinoids, natural compounds that can act as pesticides and deterrents to pests.
The team also discovered that predator insects, including lady beetles, were more likely to feed on caterpillars found on corn grown in pea-conditioned soil. Researchers believe cover crops may influence not only plant health but also the quality of insect pests that feed on those plants.
“This allows me to go into the field and tell growers that the cover crops they select changes its potential resistance to pathogens and insects, and that each insect species may respond differently to each crop,” said Jared Ali, associate professor of entomology and director of Penn State’s Center for Chemical Ecology.
“That's an insight we didn’t have before. There was anecdotal evidence, maybe some farmers had noticed a difference, but now we have the science behind why that's really possible and what mechanism allows that to happen.”
The researchers planted corn in soils previously conditioned by pea, radish, and triticale cover crops, as well as fallow soil. Their findings revealed important differences in plant defense chemistry and predator behavior.
“What my group has been doing is looking for ways that some of the plants still have the ability — still have some of those metaphorical fangs to fight off pests and disease,” Ali said. “If we can put them in the right context, what defenses still remain in our domesticated plants?”
Researchers believe the findings could help farmers use cover crops strategically to improve pest management while supporting sustainable crop production.
Future studies will explore how soil organisms, nutrients, crop yields, and plant development interact with these natural defense mechanisms.
Photo Credit: gettyimages-klosfoto
Categories: Pennsylvania, Crops, Corn