Production Blog

Caterpillar Droppings

Emily Unglesbee
By  Emily Unglesbee , DTN Staff Reporter
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Most U.S. farmers aren't familiar with Helicoverpa armigera, but a lot of resources are devoted to looking for it on American soil. (Photo by Gyorgy Csoka/Hungary Forest Research Institute, courtesy Creative Commons)

DTN's recent reporting on the Helicoverpa armigera caterpillar's chances in the U.S. presented us with a dilemma. How do we report on the risks of a pest that hasn't arrived without sounding like Chicken Little?

Step One: Nix the alternate title: "The Caterpillar is Coming! The Caterpillar is Coming!"

Step Two: Talk to as many impartial sources as will answer your calls and end up with a mound of information, much of which won't make the final story.

Most story trimmings are best left lying on the cutting room floor, but two stood out as interesting and maybe even important:

1) Our government spends a lot of time trying to keep invasive pests out of the country, and they chronicle these efforts on some pretty neat websites that are worth a view.

2) Many of the people we talked to didn't have the foggiest idea what we were talking about. Yet we wrote a story about it anyway.

Here are those thoughts, dusted off and set back on the table.


Calculating the risk of a Helicoverpa armigera invasion in the U.S. is extremely complicated. In fact, entire government agencies are devoted to figuring this out... and we're still not sure.

Invasive diseases and insects have been making their way into the U.S. with increasing frequency as global trade expands. They sneak into travelers' luggage, infest imported fruits and vegetables, or cling to the bottoms of ships and cars.

The USDA's Animal and Plant Health Inspection Service (APHIS) keeps a blacklist of pests it prefers to keep out of the country. (Since 2003, Helicoverpa armigera has been high on that list.)

The agency also rakes in data on climate, vegetation, and port inspections to create risk assessment maps of the country, which have the added benefit of being colorful and pretty. Check out the risk maps for dozens of invasive pests and see how your county fares:…

Should Helicoverpa armigera ever make it past inspectors into the field, a surveying program called the Cooperative Agricultural Pest Survey (CAPS) would most likely spot it. This agency surveys agricultural fields each year for priority pests. If you're feeling paranoid, pick a pest or two and see if scouts swept through your county:….

Since 2004, scouts have surveyed parts of 39 states for Helicoverpa armigera. Some states such as Utah, Wyoming, Idaho, Georgia, and Alabama have had nearly every county searched for the pest in the past decade. See the CAPS surveying maps for armigera here:….

And if you have a hankering to go hunting yourself, you can find instructions for finding and trapping the caterpillar here:….


Interview after interview with respected U.S. entomologists wound down to the same conclusion: This pest could be a big deal for American farmers.

At the same time, tossing the name Helicoverpa armigera out to farmers and less specialized scientists turned up different responses. Usually "Bless you!" or "Huh?"

In their defense, the Brazilian invasion of armigera marks the first time this caterpillar has crawled into the Americas in roughly 1.5 million years.

However, in the Old World (Europe, Asia and Africa), you'd probably have trouble finding a farmer who isn't uncomfortably familiar with Helicoverpa armigera. Historically, the caterpillar has devastated cotton growers in China, Australia, and India, ripped through tomato crops in New Zealand and India, eaten more than half the foliage off of Monterey pines in New Zealand, and destroyed entire chickpea and pigeonpea crops in two growing seasons in India.

More recently, Helicoverpa armigera has already cost Brazilian farmers millions of dollars in crop damage and insecticides. Brazil's Agriculture Ministry has already been forced to approve a previously unlabeled pesticide, after more traditional insecticides failed to control the caterpillar this year.

The Brazilian pest is still miles (and many import inspections) away, but we felt its aggressive nature, government attention, and previous visits to the U.S. (4,431 as of 2000) added up to a worthwhile story.

The true extent of this pest's impact in Brazil probably won't be known for several years. The risk it poses to U.S. farmers will also remain uncertain -- for now.

In the meantime, we'll be keeping our eyes on this new southern neighbor. Just in case.



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Denes Szieberth
1/24/2014 | 3:16 PM CST
The same harmful and unpredictable insect in Hungary. Not only in corn but in beans, vegetables etc. In 2003 it caused a huge problem in sunflover. In light traps can be detected year by year with different peaks of gradation.