U.S. organic apple and pear production may not take as radical of a blow as originally thought from the upcoming regulatory ban on oxytetracycline, an antibiotic used to treat fire blight.

Regulatory changes by the National Organic Standards Board will prohibit organic producers from using the antibiotic starting this October. An initial producer survey indicated that up to 80% of organic pome fruit growers could switch to conventional methods due to the ban.

Although the change is still expected to cause disruption, new data from organic producers looks a lot less scary, explained David Granatstein, sustainable agriculture specialist for the Washington State University (WSU) Center for Sustaining Agriculture and Natural Resources.

"Based on surveys of growers that I have conducted, they are feeling more confident now than two years ago about having a viable alternative control method," Granatstein told www.freshfruitportal.com.

"In my latest survey from January 2014, 45% of growers said they expected to expand organic tree fruit acres, 39% expected to stay about the same, and 11% said they planned to decrease.  It looks like decreasing some of the more susceptible apple varieties is still a possibility for many."

Granatstein said regional reactions may vary, however, with some sectors of the U.S. indicating greater confidence than others.

"The Midwest and Eastern commercial organic growers - there are few - are more concerned, as shoot blight in summer can be a bigger issue for them, and the biocontrol Blossom Protect is not effective against this. Also California growers with extended bloom periods during ideal fire blight weather may find it difficult to keep up with treatments and to afford them," Granatstein said.

One of the major drawbacks of Blossom Protect is its higher cost.

"Blossom Protect is considerably more expensive than antibiotics, especially because it requires a large amount of a buffer material to be applied with it.  In many cases, a grower will need to apply this prior to a model signal to treat, and it may turn out that treatment was not necessary.  So probably more sprays overall, and most of them more expensive products," Granatstein said.

For pear growers, adapting new methods may prove more difficult, given the fruit's greater susceptibility to the disease, said Mike Willett, vice president for scientific affairs at the Northwest Horticultural Council.

"For pears [antibiotic use] is substantially higher. The majority of acres are treated with conventional antibiotics," he said, explaining many apple growers have already adapted to alternative methods.

"The main concern has been the fact that there hasn’t really been enough time to completely evaluate under commercial conditions some of the newly available alternatives."

One of the greatest concerns at the moment has been what Willett described as the "fear of not knowing".

While alternative treatment methods exist, Willett said the judgment on oxytetracycline and other antibiotics felt rushed. The October ban comes before the expected 2015 release of a promising, non-antibiotic control method, being developed by the USDA-OREI.

When asked why the ban had not been better aligned with the release of the new United States Department of Agriculture (USDA) Organic Agriculture Research and Extension Initiative (OREI) method, Willett said the industry simply did not know.

"We don’t think it had anything to do with facts or science. I think the folks that are opposed to antibiotics bent the truth," he said.

Leading up to the new regulations, Willet said the many organizations have been active developing new treatments and preparing growers for the transition. One among them has been the Organic Center, behind a new grower manuel, co-authored by Granatstein.

"Good sanitation, good spray coverage, controlling tree vigor (not too much nitrogen) are all proven strategies that help. If a high infection is predicted, or an orchard has a history of fire blight, then growers will need to have a more proactive spray program than waiting for the disease prediction model to signal an antibiotic treatment," Granatstein said.

"This could include pre-bloom copper to suppress bacteria growing in cankers; use of Blossom Protect one or more times during bloom; use of Serenade or Cueva at petal fall.  It will likely take a combination of materials to provide the same control that antibiotics did."

Related stories: Organic U.S. growers look for alternatives to treat fire blight

U.S.: concern grows over fire blight treatment options

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