Energy and Environment Reporting for Texas

Quarantine in South Texas as Mexican Fruit Fly Invades, Again

Photo courtesy of the USDA http://bit.ly/10mLkc8

Recently larval Mexican fruit flies were spotted in Texas.

Don’t let its size fool you, the Mexican Fruit Fly is a serious threat to Texas’ agriculture.

Authorities spotted larval Mexican Fruit Flies in South Texas and quarantined an 85 square mile area to contain the dangerous pest and its insidious larvae, according to the Texas Register.

The quarantine is one of many used over the years as part of a strategy to stave off an infestation of the fly, a pest with the potential to devastate an integral part of the South Texas economy. But while Texas and federal agencies use a variety of methods to keep the little bug at bay, some measures can adversely affect farmers.

“In terms of what the quarantine means, first of all, it’s the extra cost,” says Ray Prewett, President of Texas Citrus Mutual.

A fruit quarantine isn’t like a human quarantine for a disease, Prewett told StateImpact Texas, it’s not as if nothing can leave the quarantine zone. The fruit can leave, but it has to be fumigated or sprayed. That costs money. Also, fumigating the fruit early in the season can cause cosmetic damage to the peel. Fortunately, this year’s quarantine was instituted late in the season so not much fruit will be affected.

But every year brings the possibility of a new infestation. Prewett says the multi-pronged eradication program administered by the U.S. Department of Agriculture (USDA) and Texas Department of Agriculture has worked well, but there are some areas it could improve to ensure Texas’ citrus producers and economy aren’t harmed in the future.

The cornerstone of the USDA’s efforts to eradicate the Mexican Fruit Fly is the mass release of sterile male flies. Those sterile flies mate with females, which then lay sterile eggs and break the fly’s life cycle.

In addition, Bryan Black, Director of Communication for the Texas Department of Agriculture, says the USDA uses an array of bait traps to capture and monitor the fly, computer models to track quarantine effectiveness and sanitation of fruit packing plants. It’s a complex system that helps maintain Texas as the third largest citrus producer in the country behind California and Florida.

“Texas citrus contributes more than $140 million annually to our state’s economy, (it’s) a valuable part of Texas’ booming agricultural industry,” Black told StateImpact Texas by email.

The real problem caused by the Mexican Fruit Fly is the larvae. Female flies deposit their larvae inside of a variety of fruits including citrus, avocados, mangos, apples and others. The larvae feed on the fruit, turning it into a mushy, rotten, unmarketable mess.

The eradication system has worked well so far. The fly, “among the world’s worst pests,” according to the California Department of Agriculture, has hardly proliferated. It was even considered eradicated in January of 2012 after three consecutive years without a sighting or trapped fly in the state.

But the system could improve, says Prewett. For one, the release of sterilized flies is concentrated mostly in Hidalgo County. While the strategy has worked well, Prewett says these sterile releases should expand to encompass more residential areas where backyard citrus growing is common and also more commercial areas beyond Hidalgo.

Abandoned groves are another problem. Two abandoned groves in the Rio Grande Valley were found to have fly larvae in their fruit last year.

“Those abandoned groves, they have fruit on the trees but the fruit wasn’t harvested and that’s just the perfect habitat or host for the Mexican Fruit Fly,”  Prewett said.

The USDA also does trapping and sterile release south of the border in Mexico. But due to ongoing violence and safety problems, those efforts have been limited, Prewett said.

David Barer is a reporting intern with StateImpact Texas.


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