The dining time of different insects impacts a plant’s defenses and nutritional quality — a complexity uncovered in new research with implications for pest management strategies.

A piercing-sucking, virus-carrying aphid has long worried pea plant farmers, but a more innocuous-seeming weevil that only takes tiny bites from leaves was found to also play a significant role in plant health. Depending if the weevils eat before, or after, the aphids, they can increase or decrease the plant’s ability to fend off the virus.

While many studies have focused on the impacts of a single pest, this study, published Aug. 4 online in Molecular Ecology, is one of the few to look at the interaction of several antagonists, in this case, two pests and a virus.

«Plants in the field have a chance of being exposed to many different types of biotic stress elements, what we call antagonists,» said Saumik Basu, a WSU post-doctoral fellow and the study’s lead author. «Based on how these antagonists are coming to the plants, that can change the plant responses and ultimately leads to changes in their overall productivity.»

Through a set of greenhouse experiments, Basu and colleagues from the Crowder Laboratory at WSU and Cornell University attempted to understand what happens to the pea plant fields of Eastern Washington’s Palouse area. In the field, plants face alternating infestations of pea leaf weevils, Sitona lineatus, and pea aphids, Acrythosiphon pisum, and a pathogen the pea aphids are also known to carry, Pea enation mosaic virus, or PEMV.

The researchers created experiments where first the weevils feasted on the plants then the aphids, and others that reversed the order. They also included scenarios where the plants were infected with the virus and some where they did not as well as a control group.

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Materials provided by Washington State University. Original written by Sara Zaske. Note: Content may be edited for style and length.