Near- Infrared Means Lights Out for Stored-Grain
Insects By Linda
December 15, 1997
Scanning individual wheat kernels with the energy of near-infrared
(NIR) light waves--a zone of the spectrum invisible to the human
eye--can reveal hidden insect infestations that lower wheat quality.
NIR can also identify and kill the pests, according to scientists
reporting findings today in Nashville, Tenn.
In studies last June, exposing wheat kernels to NIR killed 100
percent of the rice weevil larvae infesting them. Scientists with the
Agricultural Research Service
ran the tests. The ARS scientists are the first to combine NIR with an
automated grain handling system to rapidly detect hidden insects in
wheat kernels. They envision using the technology with grain samples
or with grain on conveyor belts at storage and food-processing
Damage from larvae of the lesser grain borer, rice weevil and maize
weevil costs the U.S. wheat industry about $500 million annually.
Detecting the infestations has been a serious problem. Grain storage
operators can save on fumigation costs if they know which pest is the
main culprit in their grain bins. But while a rice weevil looks like a
granary weevil, NIR technology quickly reveals which is which.
Each insect species has a unique light signature based on its body
content of carbon, hydrogen and nitrogen. This body chemistry
determines how much light is absorbed. In response, the NIR instrument
produces a graph--much like a cardiogram--with the telltale peaks and
valleys unique to a particular insect species.
The NIR instrument includes two pieces of equipment known as a diode
array spectrometer and a wheat singulator. The instrument was
developed by Perten Instruments, Springfield, Ill., and engineers at
ARS Grain Marketing and
Production Research Center, Manhattan, Kan.
Today, entomologist James E. Throne reports on the NIR studies in
Nashville at the annual meeting of the Entomological Society of
America. Throne works at ARS Manhattan center.
Scientific contact: James E. Throne, ARS
Grain Marketing and Production
Research Center, Manhattan, Kan, phone (785) 776-2796, fax
(785) 776-2792, email@example.com.