SEPTEMBER
1991

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

9-12-91

CORN BORER MURDER

If murdering a corn borer moth were a crime, all nighttime motorists would be in jail.  Those cream-colored moths fluttering in snow storm-like density in the glow of headlights are corn borers.  They are the victims that end up on radiators, in grills, or as unsightly grease spots on windshields and headlights.

In their immature or larval stage, corn borers are major pests of corn.  As worms, they bore in the corn stalk—that's the basis for their name.  Such activity weakens the plants and can result in yield reduction.  Those borers become moths, and the moths in turn lay eggs that hatch into borers, so the cycle goes.

In most years, the borers are still chomping on corn plants during late summer and fall in preparation for winter.  However, the unusually warm summer of 1991 has accelerated development of many insects, including corn borers.  The moths that were flying in August normally do not emerge until the following June.  The early emergence coupled with high numbers have created the nightly “storm of moths.”

Corn borer moths spend their days lounging around in grassy areas such as roadsides and creek banks.  When the sun goes down, these moths take to flight, seeking suitable plants on which to lay eggs.

Corn borer moths, like many other night-flying insects, are attracted to lights.  Consequently, moths are frequently found congregating around porch lights and windows far from their home cornfields.

However, drivers traveling through areas of high corn density are most likely to encounter the fluttering masses of moths.  These insects are going about their “mothly” business when the auto invades their airspace.  The stream of air flowing over the auto sucks the hapless insects into an unexpected death.

If the car is moving at 40 mph or slower, most insects safely flow over it.  However, at higher vehicle speeds, they are unable to control their density and end up in a fatal crash landing.  As a result, windshields are messy as well as hazardous to the motorist who is trying to peer down the road. 

The next morning, one can assess the mess, but be wary.  The corn borer's misfortune is a boon to another insect.   In many cases, yellow jackets have arrived on the scene and are busy extracting the moth carcasses as food for their larvae.

In nature nothing is wasted.  Of course, to most folks having yellow jackets swarming around the corn borer carnage on their auto is just adding insult to injury.

 

 

Writer: Tom Turpin
Editor: Olivia Maddox