Using Listening Devices to Detect Hidden Pest Infestations

GAINESVILLE, Florida – When it comes to most crop pests, the saying goes, “If you see the damage, then it’s already too late.” But what if you could hear the pests coming long before they cause any destruction?

University of Florida researchers are putting an ear to the soil around grape vines to detect the presence of the grape root borer, a significant moth pest of the grape industry across the Southeast. The strategy is just one of several Integrated Pest Management techniques being explored.

William Sanders, a former University of Florida graduate student under the direction of professor Oscar Liburd, received a $9,434 Southern Sustainable Agriculture Research and Education (SARE) Graduate Student grant to use acoustic devices to detect the presence of the grape root borer larvae in the soil around grape vines.

Grape root borer larva

“The larva is the stage of the pest that does the most damage,” said Liburd, a small fruit and vegetable specialist in the Department of Entomology and Nematology. “After the female emerges from the soil, she mates with the male and lays eggs on grape vine leaves, and weeds that surround the vines. The eggs then hatch and the larvae burrow into the soil and feed on the roots of grape vines. The pest is hard to manage because you can’t see it. Producers don’t know they have an infestation until their vines yellow and wilt.”

Liburd said that his research has shown that it only takes two to three grape root borer larvae to take down an entire vine.

Sanders and Liburd came up with the idea of using acoustic devices to detect the presence of the larvae based on the work conducted by Richard Mankin, a U.S. Department of Agriculture research entomologist. Mankin is a world authority on using acoustic devices for detecting hidden pest infestations.

The research called for using a device known as an accelerometer, which converts vibrations to electrical signals, and then using a second acoustic device to convert those electrical signals into sounds.

“We attached the probes to approximately 30 root systems listening for the grape root borer,” said Liburd. “We detected sounds in almost all the vineyards, but when we dug up the soil, we only found one instance where the grape root borer was present.”

Other insects and invertebrates present included various species of beetles, burrowing roaches, termites, spiders and earthworms.

The findings, said Liburd, prove that insect sounds can be detected using the devices, and if researchers can separate one insect sound from another, they can potentially identify the presence of grape root borer.

“That’s significant because it can help producers improve their management strategies that not only would be more efficient, but also would be more cost effective,” he said.

Grape vine damage from grape root borer

Currently, some farmers use a technique called mounding to control the grape root borer. Mounding involves raising the level of the soil around the base of the grape vine to about 6 inches high. Mounding forces the female to dig through more soil as she makes her way to the surface to mate and lay eggs.

“The result is that the female tends to die before reaching the soil surface,” said Liburd. “Mounding, however, is very labor intensive because you have to mound each grape vine. If you have a large vineyard, it’s a near impossible technique to practice. If we can identify the presence of grape root borer then farmers only have to mound those vines with infestation, saving them time and money.”

The process of using acoustic devices is not used extensively as an Integrated Pest Management technique, however. Liburd said that researchers are seeing more success using pheromones to disrupt mating with the grape root borer.

“The research has really taken off. We have cooperators around the Southeast, and the results they are submitting so far are very promising,” said Liburd.

Researchers are studying various pheromone products and various pheromone application techniques to confuse the male grape root borer moth and prevent the pest from mating with the female. With such a very short mating window – generally two days before the female dies – the management strategy may be the next big thing to come on the market.

“This is research where you are definitely going to get your money’s worth,” said Liburd.

In Florida alone, grape production is a $20 million industry. Without pheromones, said Liburd, 50 to 60 percent of the vineyards are potentially threatened by the grape root borer.

To read more about the research, log on to http://news.ufl.edu/2011/08/29/heard-that/. For more information on the grant, “The Smells and Sounds of a Subterranean Sessid: Mating disruption and acoustic detection of grape root borer,” log on the SARE Outreach database and search project number, GS09-082.

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Photo credits: Oscar Liburd

Published by the Southern Region of the Sustainable Agriculture Research and Education (SARE) program. Funded by the USDA National Institute of Food and Agriculture (NIFA), Southern SARE operates under cooperative agreements with the University of Georgia, Fort Valley State University, and the Kerr Center for Sustainable Agriculture to offer competitive grants to advance sustainable agriculture in America's Southern region.