Biological Control of Fire Ants

By George Grow

This is the VOA Special English AGRICULTURE REPORT.

A government laboratory in the American state of Florida is growing an unusual crop -- phorid flies. Scientists plan to release the insects in the southern United States early next year. Phorid flies are fierce enemies of another insect, the fire ant. The scientists want to use the flies as weapons in a campaign to control fire ants.

The new biological control campaign is part of a five-year program. It involves the United States Department of Agriculture and the Florida Department of Agriculture and Consumer Services.

Fire ants are native to South America. They first arrived in the United States in the Nineteen-Thirties. Fire ants are now found on one-hundred-twenty-five million hectares of land in the southern United States.

Fire ants cause thousands of millions of dollars in agricultural losses, environmental damage and chemical control costs. The insects attack humans, farm animals, and other animals. They leave small, painful cuts on their victims.

Phorid flies can destroy fire ants. First, a female fly injects an egg into the body of a fire ant. The resulting larva digs into the ant's head. The larva grows and releases enzymes that cause the ant's head to fall off. Inside the head, the larva develops as an adult fly. Phorid flies attack only fire ants. They are not considered dangerous to other ants or animals.

Scientists have spent years testing the effectiveness of different phorid flies against fire ants. Three years ago, the Agricultural Research Service released thousands of Brazilian phorid flies in three areas in Florida. The tests proved successful.

The research laboratory in Gainesville, Florida, has been producing about one-thousand five-hundred phorid flies every day. However, that is enough to be released in only two or three areas each month.

Florida state officials offered to help. Their laboratories are expected to increase the production of the insects next year. Scientists will release the phorid flies in eleven southern states, including Florida. Over the next few years, officials will study the flies and their ability to live in areas where they are released. They also will study the spread of the insects to new environments and their effect on fire ant populations.

This VOA Special English AGRICULTURE REPORT was written by George Grow.