Texas officials hope they’ve caught citrus greening early

02/21/2012 08:05:00 AM
By Vicky Boyd, Editor

With the recent find of citrus greening in the Texas Rio Grande Valley, state citrus industry officials say they hope their years of planning have helped limit the disease spread from an area near McAllen.

“We knew citrus greening was going to come one day,” says Juan Anciso, a Texas AgriLife Extension specialist in Weslaco. “But the past few years, we’ve had a voluntary areawide spray program to spray for the psyllid. So surveillance and preventive measures have been occurring for several years.”

Citrus greening, also known as huanglongbing, was confirmed in nine Valencia trees and five grapefruit near San Juan earlier this year.

The owner has destroyed the trees. As a result, the Texas Department of Agriculture enacted an emergency quarantine extending 5 miles out from the finds.

Crews continue to conduct extensive surveys and collect samples to determine the extent of the infestation.

The quarantine bars homeowners within the zone from moving citrus plant material within the zone or in and out of the zone.

A protocol for commercial fruit within the quarantine requires that trees be sprayed with a pyrethroid one to two days before harvest.

Then workers must put the fruit on a sorting table to remove all leaves and twigs before placing it in bins. Ray Prewett, president of Mission, Texas-based Texas Citrus Mutual, says it’s too early to say whether the disease has spread outside the quarantine.

“It’s an obvious concern, but we’re not jumping to conclusions,” he says. “About one-third of the commercial citrus within that 5-mile radius has been tested, and so far, no positives.”

Prewett points to the voluntary areawide spray program that growers have been conducting against the Asian citrus psyllids for the past two years as reason for hope.

Growers representing more than 80 percent of the citrus acreage in the Lower Rio Grande Valley are participating, Anciso says.

The goal is to have all growers treat at once. That way, psyllids don’t have an opportunity to escape a treated grove for the safety in an untreated grove.

In addition, the U.S. Department of Agriculture and Texas Department of Agriculture had conducted extensive surveys and tested 35,000 insects and 20,000 leaf samples before one positive sample was found.

Even before the positive find, Prewett says a group of Texas growers and researchers had planned to visit Florida to gain firsthand knowledge of that state’s battle against citrus greening. Now the visit takes on more importance, he says.

Ansico says their main goal now is educating homeowners about not moving citrus plant material in or out of the state or the quarantine area.

“That’s a big concern,” Prewett says. “We have door yard properties certainly close to commercial citrus. The first detection was in this commercial Valencia grove, but we are not saying that is how [greening] first came here.”

Part of the homeowner education will be how to safely spray citrus trees to reduce psyllid populations, Anciso says.

A list of products registered for use by homeowners is available at http://www. texascitrusgreening.org.

The Texas Rio Grande Valley has about 28,000 acres of citrus, and harvest is about 40 percent complete.

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