Blacksburg, Virginia
June 11, 2007
A
Virginia Tech plant pathologist has developed autonomous
unmanned aerial vehicles (UAVs) to detect airborne pathogens
above agricultural fields.
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David Schmale prepares to collect Fusarium
samples |
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David Schmale, assistant professor
of plant pathology, physiology, and weed science in the College
of Agriculture and Life Sciences, has not only linked
agriculture and engineering with his interdisciplinary research
but has also given scientists an unprecedented glimpse into the
life of microorganisms hundreds of meters above the surface of
the earth.
“Until recently, researchers used autonomous UAVs for military
applications, but now we can apply this cutting-edge technology
to agriculture,” said Schmale, who is an affiliate faculty
member in the Virginia Center for Autonomous Systems (VaCAS), a
Virginia Tech research center that facilitates collaboration
related to autonomous systems in the College of Engineering, the
College of Agriculture and Life Sciences, and the College of
Natural Resources.
Scientists have used aircraft to monitor the movement of
airborne pathogens for years, but Schmale is the first plant
pathologist to use an autonomous system for this process.
“Autonomous UAVs have distinct advantages over a sampling
aircraft operated via remote control,” Schmale explained.
“First, the autonomous UAVs maintain a very precise sampling
path. We can establish a GPS waypoint in the center of an
agricultural field, and the autonomous plane can circle around
the waypoint at a set altitude, with about a meter variation up
and down. Second, the autonomous technology enables us to have
coordinated flight with multiple aircraft. In other words, we
can have two aircraft sampling pathogens at the same time but at
different altitudes.”
Schmale has used the small, self-controlled planes to collect
samples of the fungal genus Fusarium tens to hundreds of meters
above the surface of the earth. This genus contains some of the
world’s most devastating plant and animal pathogens and remains
largely a mystery to scientists who do not have a firm
understanding of its ability to travel long distances in the
atmosphere. By placing antibiotics in the sampling collection
plates, researchers can ensure that only Fusarium will grow on
the plates. Over the course of 75 different UAV-sampling flights
above agricultural fiends at Virginia Tech’s Kentland Farm,
Schmale and his colleagues collected more than 500 viable
colonies of Fusarium, representing at least a dozen species.
“For 11 of these Fusarium species, this is the first report of
their ability to be transported great distances above the
surface of the earth,” Schmale said. “Our work has important
implications for the rapid spread of invasive plant and animal
pathogens in the United States.”
Schmale’s research is not limited to the study of Fusarium,
however. He has expanded his interests to explore entire
microbial populations in the atmosphere—a type of research he
calls “aerogenomics.”
“One of the species we collected with our autonomous UAVs
appears to be a bacterium known only to exist in a cavern in
Arizona,” he said. “What was that bacterium doing 100 meters
above Kentland Farm? In many of our other samples, we have found
organisms that have never been cultured before. Some of these
microbes may thrive only in the atmosphere, and many of them may
be new to science.”
This and other fascinating results have led Schmale to
hypothesize that some airborne microorganisms have “novel
biochemical processes for interacting with each other as a
community of organisms in the atmosphere.” He explained, “We
know that microbes mediate important biochemical processes in
the soil and the ocean. It is not so farfetched that a similar
drama unfolds in the atmosphere, which we already know is
teeming with microbial life.”
Although Schmale is not currently conducting his research for
the armed forces, his work has a definite biosecurity element.
“Many plant pathogens are transported over long distances in the
atmosphere, threatening agriculture in the United States from
both inside and outside the borders of the country,” Schmale
said. “An increased understanding of the dynamics of plant
pathogens in the atmosphere is essential for establishing
effective quarantine measures, preventing the spread of plant
disease, and mitigating potentially damaging events targeted at
our nation’s agriculture and food supply.”
VaCAS member research activities range from fundamental control
theory to vehicle development to applications for science,
security, and commerce. Schmale and other affiliate faculty
members in the College of Agriculture and Life Sciences bring
the fields of plant pathology, entomology, and horticulture to
VaCAS.
By
Michael Sutphin |
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