Bactericide Grower Trials for HLB ‘Extremely Variable’

Ernie NeffBactericides, HLB Management

HLB

Stephanie Slinski

Stephanie Slinski, Citrus Research and Development Foundation bactericide project manager, discussed grower trials on the use of bactericides for HLB at the Florida Citrus Growers’ Institute in Avon Park on April 4. She summarizes the presentation.

“We have a series of field trials set up throughout Florida to test the efficacy of oxytetracycline and streptomycin just in the grower program,” Slinski says. “So these are very simple field trials to evaluate controls and treatments within grower groves.”

So far, she says, results “have been extremely variable … Some groves are good, some look not so good. I don’t have a conclusion at this time.” In some trials, fruit drop was less and yields were higher in treated groves; in some cases, fruit drop was less and yields were higher in untreated groves. “And I can’t tell you why, and I don’t know if I’ll ever be able to tell you why,” Slinski says.

“Because these are perennial crops, it is possible that it will take a couple of years to see results,” Slinski adds. “It takes a while for the trees to repair themselves and to take on that healthy appearance and start improving yield and decreasing fruit drop.” Researchers advised growers that bactericides could take a few years to show maximum results when growers were first authorized to use the products in the spring of 2016.

Slinski offered no recommendations regarding bactericides use. “We are just trying to help growers make better decisions for themselves and provide data for them to make these decisions,” she says.

As usual, the annual Florida Citrus Growers’ Institute drew several hundred to the South Florida State College campus. Topics addressed included citrus tree health, Asian citrus psyllid management, post bloom fruit drop, bactericides and food safety. With the exception of Slinski, speakers were with the University of Florida’s Institute of Food and Agricultural Sciences.

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About the Author
Ernie Neff

Ernie Neff

Senior Correspondent at Large