A novel strategy with the potential to improve pest management for a variety of crops worldwide is being developed by WSU associate professor of entomology David James. He has coined the acronym HIPPOs (Herbivore-Induced Plant Protection Odors) to indicate his research focus.
James and his team are working on multiple field experiments with hops and grapes for improving the control of mites and insects.
Previous studies have shown that plants, when attacked by insects and mites, respond by emitting distress signals. These signals take the form of a bouquet of volatile chemicals, the signaling “language” plants use to warn neighboring plants that they also may be attacked and should defend themselves.
“What’s interesting is that predatory and parasitic insects and mites also are fluent in plant language, and the plants know this,” James explained.
Predators that prey on parasites harmful to the plant know there will be food and hosts available.
“The chemical dialogue plants produce when attacked benefits not only the plants, but the ‘bodyguards’ they recruit for protection,” James said.
Although scientists have been studying plant-to-plant and plant-to-insect conversations for more than 20 years, there are many questions that James’ team is hoping to answer. For instance, can the conversations plants have with each other and with beneficial insects be faster and louder? Can these improved conversations improve pest management efforts?
“There is no universal plant language,” James said. “Different plant species seem to have their own unique languages. Grape talk is different from, say, bean talk.
“However, there are some ‘words’ that appear to be fairly common among plant languages, so they are understood whether emitted by grapes or beans,” he said.
More research is required in regard to deployment rates and methods before HIPPOs can be used optimally in practical crop pest management. However, dispensers containing HIPPOs are available commercially, and some growers are using them with good results.