Better safe than sorry: That’s how Lower Rio Grande Valley citrus experts reacted to last week’s quarantine of Florida citrus.

On June 6 the U.S. Department of Agriculture announced that Florida citrus growers will be barred from sending their fresh fruit to other citrus-producing states this season to prevent the spread of citrus diseases.

“The implementation of the quarantine was based on the widespread presence of citrus canker in Florida that could be spread to other citrus-producing areas on contaminated fruit,” said Dr. Julian Sauls, aTexas Cooperative Extension citrus specialist in Weslaco.

Canker is not a threat to humans, but it is a highly contagious bacterial disease that causes unsightly lesions on leaves, twigs and fruit, leaving the citrus unmarketable. It is spread by wind, rain and people who can unknowingly transfer the infection on their person or by moving infected plants, Sauls said.

The quarantine prevents the shipment of Florida citrus to five U.S. territories and six states, including Texas and California, two of the Valley’s largest citrus markets.

Florida’s $9 billion citrus industry has been battered by two hurricane seasons that ruined crops and spread canker throughout the state. In January, the USDA announced it would no longer fund the destruction of all citrus trees within a 1,900-foot radius of an infected tree.

Florida growers have also been hit with citrus greening, another bacterial disease that leads to tree death. Neither have been detected in Rio Grande Valley orchards, but they do pose a looming threat.

“These bacteria have no known cures, other than the complete destruction of infected trees,” said Dr. Erik Mirkov, a virologist and microbiologist at the Texas A&M University System Agricultural Research and Extension Center at Weslaco. “They literally threaten the very existence of citrus production in the United States and elsewhere.”

Mirkov has developed transgenic varieties of citrus trees that are being tested in Florida for resistance to both canker and greening.

Preliminary results look promising, Mirkov said.

Florida grower organizations were upset with the quarantine, claiming that fruit without disease symptoms should be cleared for shipping, Sauls said.

“The fear is that fruit with canker lesions would get by inspectors and make its way to Texas,” he said.

Dr. John Da Graca, deputy director of the Texas A&M-Kingsville Citrus Center at Weslaco, said that risk of transmission is being studied by USDA scientists in Florida.

“They’re trying to determine whether infection can be transmitted from fruit that has bacteria present yet is asymptomatic, or not yet showing symptoms,” he said. “And there’s the question of whether fruit can acquire the bacteria from a bin, for example, that previously contained contaminated fruit. There’s a lot yet to be answered, so while the risk may not be high, the more we can do to eliminate risk, the better.”

Ray Prewett, president of Texas Citrus Mutual, a commodity group in Mission, agreed, and said his organization was supportive of the quarantine action.

“We’re obviously concerned about the possibility of getting canker,” he said. “It would be devastating to us. There are legitimate reasons and merits for the quarantine and what USDA did, but we’re not sure of what the impact will be to growers and consumers.”

The quarantine means Valley growers will be without competition from Florida citrus in California and Texas. But both Prewett and Sauls agreed the market would have been favorable for Valley growers anyway since this is the third year that grapefruit production from Florida has been severely limited by urbanization, hurricane damage and citrus diseases.

How long the quarantine will last and whether it will affect the international citrus import/export markets is yet to be determined, Prewett said.