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Virginia Tech research team fights the spread of damaging invasive pests

April 4, 2016

Damage to tomato leaf caused by tomato leafminer.

Crops damaged by tomato leafminers.
The invasive South American tomato leafminer is destroying tomato crops across Europe and West and Central Africa, creating blotch-shaped mines in the leaves that often lead to infections. Source: IPM, Virginia Tech.

Across the world, the tomato leafminer is wreaking havoc on agricultural producers. The relentless march of these pests inspired a team of Virginia Tech researchers to apply new methods of modeling and simulation previously used in infectious disease research to halt their spread. A new USAID grant will help them do just that.

The tomato leafminer, Tuta absoluta, is an innocuous-looking moth, easily hidden by the burgeoning foliage of young tomato plants. But once the eggs of the moth hatch, the larvae tunnel through the plants’ leaves, quickly giving a once green, productive field a scorched appearance. In Europe, West and Central Africa, and the Middle East, these pests have caused 50 percent to 100 percent crop loss since their accidental introduction to Europe in 2006.

“Entomologists normally use CLIMEX, a software modeling program that estimates the geographical distribution of an insect, and insect life tables, an analysis of an insect’s life cycle, to theorize how an insect will spread,” said Muni Muniappan, entomologist and director of the agricultural development program that is managing the grant. “But the Biocomplexity Institute is introducing human movement into the equation. This is a new angle.”

Managing these insects is not as simple as spraying insecticides. Virginia Tech’s Integrated Pest Management Innovation Lab works to provide solutions to farmers of developing nations using integrated pest management techniques that take into account the long-term health of people and ecosystems, as well as sustainable agricultural productivity.

However, halting the incredibly fast spread of these pests can be very difficult. Thus, researchers are turning to computational modeling in an effort to better understand when and where the insects will appear next. Using agent-based models in a novel approach, the research team will incorporate multiple data sources and find the most significant factors in the spread of these insects.

In the tomato leafminer study, the research team will view pest dynamics as an integrated biological, informational, social, and technical system consisting of several interacting models. This interaction-based approach is aimed at capturing the complexity of pest dynamics.

 A key feature of this approach is understanding how humans hasten the speed at which pests spread. This includes not only human mobility but also supply chain infrastructures used to move goods across continents. These systems can have unintended side effects, one of which is the spread of invasive pests. This study will lead to a much better understanding of how human systems contribute to the spread of pest infestation.  

“Our model will be an extremely useful tool for risk analysts, domain experts, and policy makers to develop strategies to combat these pests. Further, the methodology will not be limited to studying the tomato leafminer, but can be applied to any agricultural invasive species,” said Abjijin Adiga, research faculty member at the Biocomplexity Institute.

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