Hermetic bags save African crop,
but not how experts once thought
February 23, 2012
By Brian Wallheimer
The hermetic grain storage bags that cut off oxygen to weevils and have saved West and Central African farmers hundreds of millions of dollars by putting the brakes on the insects' rapid multiplication don't merely suffocate them as once thought, a Purdue University study shows.
More than 25 years after introducing the Purdue Improved Cowpea Storage (PICS) bags to farmers in Africa, Larry Murdock, a professor of insect physiology, discovered that weevils produce much of their water themselves through metabolic processes. When oxygen in the bags decreases, the weevils cannot use it to create water, and instead of suffocating, they eventually die of thirst.