Less than two months after Texas—and the United States at large—were declared free of the citrus-destroying Mexican fruit fly, a mated female Mex Fly was discovered in a trap in Cameron County Mar. 2, forcing USDA- APHIS to implement an 81 square mile regulated area to contain the pest and to initiate rules on how the Valley citrus industry must deal with the new development.

Currently the Texas Department of Agriculture is working on an official quarantine zone plan that will isolate a nine-square mile area around where the specimen was discovered. Until that takes place, USDA is enforcing what they term an “individual hold notice” of non-harvested fruit in the regulated area.

Larry Hawkins, spokesman for USDA-APHIS, says the federal agency is waiting for state action to prevent the USDA from issuing a broader quarantine area that would involve the entire State of Texas.

“USDA can issue only a statewide quarantine unless the state agency in charge, in this case the Texas Department of Agriculture, issues a more localized quarantine area. Once that happens, USDA will parallel the State’s quarantine zone and issue control guidelines,” Hawkins said in a telephone conference Mar. 6.

Long-time citrus pest

The Mexican fruit fly has plagued citrus growers in a broad area of the U.S. since first detected in 1927. While the fly threatens the production of citrus, it poses no health issues related to human consumption. The regulated area in Cameron County involves only one commercial grower.

“This detection is ironic because in January this year a Mex fly quarantine of Hidalgo County was lifted after research and trapping programs indicated the problem had been controlled there,” Hawkins added.

Cameron County borders Hidalgo County and has previously been troubled with fruit fly quarantines. But USDA-APHIS officer-in-charge Robert Vlasik in McAllen says regulatory and grower response to this latest detection has been swift and says most fresh fruit grown within the control area has already been harvested, processed and shipped. He also noted the mated female was discovered in a trap and not on standing fruit.

“Under terms of the administrative hold, citrus producers in the control area have three options,” Vlasik says. “The options include a bait spray program that meets APHIS requirements, fumigation, or taking fruit from respective groves to a juicing plant.”

The exception to the options is fruit located within one mile of where the mated female was trapped. In this area fruit must be fumigated before being released, unless otherwise noted by USDA.

Hawkins says the commercial grove affected by the hold includes a 120-acre grove operated by a single grower. But Vlasik says inspections of fruit at area flea markets and roadside stands will also take place to make certain no infected citrus is moved outside the control zone unless it first meets control requirements.

According to a published statement from Joey Trevino of Texas Citrus Mutual, recommended products for a regulated bait spray program include Malathion or Spinosad. The statement indicates it is important for those who choose to take part in the bait spray program to know that treatments must take place at a 10- to 14-day interval for Malathion and 7 to 10 days for Spinosad. The first application must take place no less than 30 days before harvest and applications will likely need to continue until harvest is complete.

In addition, for a grower who chooses fumigation, fumigation must take place in an approved fumigation chamber by a certified operator under an APHIS compliance agreement and monitored by APHIS and/or TDA personal.

Texas Department of Agriculture spokesman Bryan Black confirms detection of the mated female and says control efforts have been put in place.

“Control and treatment is under way, bait sprays will be applied to host trees within 500 meters of the detection site by [the local citrus] industry. The release of sterile male Mexican fruit flies will be increased in the area,” Black says.

The quarantine is expected to be in place for approximately four months.

“The Texas Department of Agriculture and USDA are working with local growers to control this pest and protect our important Texas agriculture industry,” he added.