Warding Off Pests by Way of Nematode Odors

— Written By

Texas A&M AgriLife Communications | 2/27/2018 | Morning AgClips

COLLEGE STATION, Texas — A recent study revealed insect-killing nematodes also produce distinctive chemical cues that enhance plant defenses and deter Colorado potato beetles.

Entomologists from Texas A&M University, including Dr. Anjel Helms, who led the study, and Penn State University took a look at whether Colorado potato beetles and potato plants responded to the presence of entomopathogenic nematodes, EPNs, or insect-killing nematodes.

Adult CPBs are oval in shape and 3/8 inch long. They have a yellow-orange prothorax (the area behind the head) and yellowish white wing covers with 10 narrow black stripes.

Photo by Debbie Roos, Agriculture Extension Agent, NC State University

The study, “Chemical cues linked to risk: cues from below-ground natural enemies enhance plant defenses and influence herbivore behavior and performance,” focused on how organisms communicate using signals and cues, specifically how organisms eavesdrop on each other as part of their survival strategies, said Helms.

“For this study, we wanted to flip things around and determine whether plants and insect herbivores can eavesdrop on chemical cues produced by a predator,” she said.

Throughout the study, Helms found that these insect-killing nematodes do produce distinctive chemical cues that both the plant and insect herbivores respond to. While the female Colorado potato beetles laid fewer eggs when the cues were present, the potato plant also increased its defenses.

This was especially important since the Colorado potato beetle is notorious for developing insecticide resistance, making them an especially devastating pest, she said.

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