Getting a "charge" from bugs in wheat
How do you spot tiny insects that might
be lurking inside grains? Give them a minor jolt, according to an Agricultural
Research Service (ARS) engineer.
Thomas Pearson, who
works at the agency's Grain Marketing and Production Research
Center, Manhattan,Kan., has found a novel and cost-effective way
to detect the pesky insect larvae that occasionally use kernels of our favourite
cereal grains as their homes.a computer software program for measuring aspects of
the sample's electrical conductance.
Kernels infested with larvae cause a
noticeable spike in electrical conductivity readings. Such increases are likely
due to the hidden larvae's moisture content.
agricultural researchers, including Pearson, are hard at work devising new and
improved methods for helping inspectors screen our nation's grain supply. Why?
Despite rigorous scrutiny of grain at flour mills and loading docks for overseas
shipments, insects, in all their earthly abundance, remain persistent invaders
of stored grains.
Hard to find
Especially hard to find
are immature insects--tender pupae and larvae that metamorphose inside the
nutrient-rich cocoon of a grain kernel until they're ready to emerge as
Pearson's detection system relies on three
a voltage source
for sending a charge through the sample, and
- a roller system for crushing a sample of
For his study, Pearson intentionally
infested batches of hard winter wheat and soft winter wheat with two of the
grain industry's most insidious foes: the rice weevil and lesser grain
He allowed the contaminated samples to
"incubate" for several weeks so that stowaway insects had a chance to multiply
and grow, and so that their unnerving presence could be independently
Pearson's specially adapted roller
mill can impressively screen about 30,000 kernels--or one kilogram of grain--a
minute, spotting 80 to 90% of those infested with insect
The cost of the device is substantially
less than other technologies for insect detection, including x-ray and
More info can also be found in the article
“How wheat kernels “sing” is a sign of their
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