“Zombie Flies” May Control Fire Ants

Fire ants

Fire ants are nearly impossible to completely eradicate.

Les Harrison is the UF/IFAS Wakulla County Extension Director

Of the many nuisances that plague the county, fire ants may be at the top of the list. Their ability to survive and colonize is remarkable. Every effort to destroy the mound seems to end in relocation–even hurricanes cannot sweep these pests away.

Finally there is hope for controlling the population of these stinging insects, though they may sound like something from a 1970s horror movie: zombie flies.

The red imported fire ant, Solenopsis invicta, is the reigning champ for taking and holding territory. The species name invicta was aptly chosen, as it means unconquerable in Latin.

Since first arriving in Mobile, Alabama around 1900, this aggressive arthropod spread rapidly through the warmer regions of the southeastern U.S.

Allegedly arriving on a boat load of bananas, fire ants quickly demonstrated their ability to be a pest on many levels.

Fire ants have shown little preference for their nest locations, thereby posing a problem for the unlucky owner of their selection. Urban, suburban or rural, just so long as there is food and moisture to consume and nest construction materials.

Agricultural producers have spent billions of dollars over the past century to eradicate or control fire ant damage to crops and livestock. Fields, pastures, fence rows and even idled equipment, offer perfect nesting sites for these ever-colonizing insects.

Likewise, city and town dwellers have endured innumerable problems caused by fire ants. Everything from lawns and flowerbeds to electrical junction boxes are subject to becoming a base of operations for these tiny conquistadors.

Treatments and control methods have ranged from limited effectiveness to ridiculous and dangerous. Grits and gasoline are examples of the latter.

Contrary to the popular myth, fire ants that eat grits will not explode. The corn-based product may cause them to relocate their nest, thinking the food is an attack, but they will set up shop nearby.

Gasoline will damage the fire ant colony, but also the water table when it leaches down.  If ignited, it poses as much of a threat to the igniter as to those ignited.

Ironically, an imported predatory fly may hold the answer to controlling, if not eliminating this seemingly unconquerable pest.

A member of the Phorid genus has shown a particular affinity for parasitizing red imported fire ants, which results in the ants gruesome death. This tiny fly, barely visible to the human eye, lays an egg on the ants thorax. When it hatches, it eats into its host and migrates towards the head.

The maggot develops on muscle and nerve tissue in the head. Ultimately, the larvae completely devour the ants brain. The ants head pops off when the Phorid fly is ready to pupate and begin the reproduction cycle again.

Luckily for other insects, only fire ants are on the menu for this particular fly. These flies have been released around the southeast, but results are still coming in. Maybe, just maybe, this invading hordes days are numbered.

To learn more about fire ants and their control in Wakulla County, contact your UF/IFAS Wakulla Extension Office at 850-926-3931 or http://blogs.ifas.ufl.edu/wakullaco.

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