The Mexican fruit fly outbreak in southern Texas can be attributed to poor handling of the growing numbers of larvae found in northern Mexico, as well as privately grown fruit trees in the area.

Dale Murden

The fly, also called Anastrepha ludens, was recently discovered in the Hidalgo and Willacy counties, and there are two quarantine zones for the fruit fly in Cameron County.

In conversation with www.freshfruitportal.com, Texas Citrus Mutual president Dale Murden explained the number of fruit flies originating from northern Mexico had been growing substantially, particularly from the state of Tamaulipas.

"The problem we have in South Texas is we're right on the Mexican border and we're seeing more larvae and fruit flies than ever before on the Mexican side."

"Apparently there's not a whole lot being done on their side of the border to curb the populations and that's why we're having the outbreaks that we’re having."

"The propagation stems from the inability on the Mexican side to do anything about it, whether it's cartel violence, or it's just not a priority, but I haven't been given specific straight answers from the Mexican side as to what they're doing down there."

Residents' citrus trees are also playing a major role in the propagation of this fruit fly.

"The issue here in south Texas, aside from Mexico, is that everybody has a tree in their backyard. And fruits are left on the tree which just harbors the insects.

"So we just preach constantly about the need to get the fruit off the trees, destroy it, so you don't increase the populations."

Curbing the spread

Texas Citrus Mutual is working with the United States Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) to take preventative measures to curb the spread of the fly.

"APHIS has a sterile rearing facility for fruit flies and they release these sterile fruit flies in the commercial groves in south Texas to prevent the wild flies from being able to mate, and render them sterile.

"That's one component of the fruit fly program down here in the valley.

"In conjunction with that when needed, when we fall into a problem area we have bait sprays that we use, organic sprays that we can use, and things like that."

Halting the propagation of these insects growing on residential fruit trees has proven a more difficult task.

"One of the hindrances we have right now with our sterile release program is that APHIS is only able to rear enough to release in the commercial groves.

"We'd love to be able to get to that capacity to where we can release in all the residential areas as well. Because residential areas here are causing us just as many problems as Mexico," he said.

Worst case scenario

Murden himself is also a grower and luckily his groves have not been quarantined, but he warns of the devastating effects the quarantines can have on growers in the area.

"Where we do have those quarantines we've gone into what we call a bait spray program per APHIS's protocol, and we're still able to pick the fruit. So we're in good shape there.

"Now if you’re unlucky and you find yourself in a core area, in other words they found the fruit fly in your grove per say, I think there's a 500 meter core for you to just not be able to pick the fruit at all.

"It can be devastating. You fall into a core in a quarantine and you can't pick your fruits, then you're out of business. You know we've got other issues, but right now this is a big one."

Murden said this industry in Texas had about 50% of its fruit harvested as of mid-February.

"If these growers were shut down now due to a quarantine or just an overall outbreak valley-wide, 50% of our crops would still be on the trees. It's starting to become a real concern."

The citrus sector of southern Texas is predominantly a grapefruit industry, producing roughly 80% grapefruit and 20% oranges.

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