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Citrus officials cleared to use bactericides another year

The Ledger – January 26, 2018

WINTER HAVEN – Florida citrus officials greeted the Environmental Protection Agency’s recent decision to extend use of three bactericides positively, although their effectiveness in moderating the effects of citrus greening remain unproven.

“It’s a good thing we got it so we can re-evaluate it,” said John Barben, an Avon Park grower and president of Florida Citrus Mutual in Bartow, the growers’ trade group. “It’s a tool in our toolbox, and we need all the tools we can get.”

The EPA had long approved use of the three bactericides — two brands of oxytetracycline and a streptomycin compound — for stone fruit and other crops but not for citrus. Research sponsored by the Lake Alfred-based Citrus Research and Development Foundation Inc., the chief scientific agency in the fight against greening, showed the bactericides could diminish the effects of greening, including increased levels of pre-harvest fruit drop and smaller fruit.

In March 2016, the agency approved a one-year “Section 18” special-use exemption for citrus. The EPA on Jan. 17 approved a third year of the exemption.

“I applaud the EPA’s decision to once again allow the use of antimicrobials on diseased citrus trees,” said U.S. Sen. Marco Rubio in a press statement following the decision’s announcement. “Our iconic citrus industry has long battled greening, and especially following the devastation of Hurricane Irma, this announcement is greatly appreciated. However, Florida agriculture is still in desperate need of disaster relief to help replace lost trees, rehabilitate flooded groves, and assist beleaguered farmers. I continue to work with my colleagues in Congress to secure this much-needed support for Florida farmers.”

Barben said he and many other citrus growers began using the bactericides right after the 2016 announcement. He said he plans to continue using the bactericides this season but at reduced rates because of the economic impact from the fruit lost to Irma.

“It’s an expensive spray,” he said. “These days you have to be careful what you put out there. You have to consider how much bang for the buck you get.”

Harold Browning, the chief operating officer at the Citrus Research Foundation, welcomed the EPA announcement, but he acknowledged the scientific data on the bactericides’ effectiveness is “noisy,” meaning there’s conflicting data.

Irma has complicated the ongoing effort to assess their effectiveness, he said. That’s because the storm dramatically reduced citrus tree yields, the number of fruit harvested per tree, one of the chief bactericide benefits.

“We’ll continue to take yield data, but there will always be an asterisk because 20 to 40 to 60 percent of the fruit was lost to Irma,” Browning said. “Although we’ll have the data, we’ll be unable to make inferences.”

Barben saw a 12 percent decline in the harvest of early and mid-season orange varieties, picked November to March, this season, he said. But he counted about one box of fruit per tree on the ground because of Irma, which would have meant an increased harvest but for the storm.

There was some good news about bactericides from Tom Jerkins, president of Premier Citrus in Vero Beach, one of the state’s largest growers, Browning said.

In a presentation earlier this week at the Florida Citrus Show in Fort Pierce, Jerkins reported a 15 percent yield increase in his 2016-17 crop of Valencia oranges, picked from March to June, he said. He had been using bactericides since 2016.

The increase is similar to results in some other studies, Browning said.

“There seems to be come convergence” on the 15 percent increase, he said.

In an email to The Ledger, Jerkins declined to make the presentation available. He could not be reached on Friday to comment.

Citrus officials hope this will be the last EPA exemption necessary because the agency is considering a request by the bactericides’ manufacturers to add citrus to the label of approved uses.

EPA officials have indicated they will have a decision on full approval of the bactericides for citrus in the first half of this year, Browning said. However, that date could be extended.

Greening is a bacterial disease that eventually kills a citrus tree. Infected trees produce fewer and smaller fruit, and they tend to drop what fruit they do produce before harvest.

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