Corn Defends Itself, Peacocks for Insect Control and Mining Mess

By The Mother Earth News Editors
Published on February 1, 1993
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PHOTOS: MOTHER EARTH NEWS STAFF
Peacocks on parade: They may be pretty, but cover your crops- and your ears!

Corn Wages Chemical Warfare

When caterpillars attack corn leaves, corn fights back.
First a signal is emitted; then the corn kernels call in a
troop of parasitic wasps to surprise attack the
caterpillars. Female rescue wasps lay their eggs directly
into the enemy caterpillars, and when they hatch, the
larvae feast on the caterpillar’s insides. As the larvae
mature, they crawl out of the caterpillars as wasps and fly
away. Mission accomplished.

All right, you buy the part about the wasps, but what is
this corn-signaling-for-help nonsense?

According to researchers Ted Turlings, Ph.D., and James
Tumlinson, Ph.D., of the U.S. Department of Agriculture in
Gainesville, Florida, corn emits a distress chemical, or
turpenoid, when it senses caterpillar saliva. (Call it the
“spit factor.”) Wasps then pick up the turpenoid’s scent
and fly over to save the day.

The two researchers are currently trying to figure out why
the corn reacts to the caterpillar’s saliva. They are also
rearing wasps in the laboratory and “teaching” them to read
the corn’s distress signal. Turlings and Tumlinson have
developed a synthetic blend (similar to the turpenoid) that
not only attracts wasps, but also poisons caterpillars and
acts as an antibiotic against fungus and bacteria.

Turlings and Tulinson hope that one day farmers will sic
’em on cornfields by the swarm.

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