The pressure is on organic apple and pear producers to evaluate and test potential alternatives to replace the use of the antibiotics streptomycin and oxytetracycline to combat the spread of fire blight. The disease not only destroys fruit, it is highly contagious among trees and can decimate  entire orchards.

This past November, The Organic Center, based in Washington, DC, released its report, “Grower Lessons and Emerging Research for Developing an Integrated Non-Antibiotic Fire Blight Control Program in Organic Fruit,” which is geared toward organic producers and provides an update on existing management practices and state of emerging research exploring alternatives to antibiotics.Fire blight is a deadly bacterial disease that not only destroys organic apples and pears, but can decimate entire orchards. (Photo courtesy of Jay Norelli, U.S. Department of Agriculture/Agricultural Research Service)

The 28-page report, available as of March 3 for download by visiting http://organic-center.org/uncategorized/organic-fire-blight-prevention-project/, includes sections on management in transitioning to non-antibiotic fire blight control as well as integrated systems approach to non-antibiotic control of fire blight for both apples and pears.

The importance of current research cannot be underestimated. “U.S. organic apple and pear growers with fire blight-prone cultivars have one growing season to test, evaluate and adopt new successful non-antibiotic fire blight management tools,” the report stated. “There is a gap between the phase-out of antibiotics in late 2014 and the final results of current research projects and the translation of this knowledge into actual organic orchard practices.”

The Organic Center has estimated that the value of the organic apple and pear market to be more than $300 million at retail. “Washington, which leads in production, currently has over 15,000 acres dedicated to organic apple and pear orchards,” said the center.

The latest report is authored by Harold Ostenson, a nationally-recognized tree fruit consultant to the organic industry, and David Granatstein, a sustainable agriculture specialist at Washington State University. According to the report, it is possible that 70-90 percent of all organic pear and apple producers may have no alternative except to switch to nonorganic management if a viable alternative is not found.

In addition to grower information being gleaned in the field, the report also discusses a study with the U.S. Department of Agriculture Organic Research and Education Initiative headed by Ken Johnson of Oregon State University in cooperation with Prof. Tim Smith (Washington) and Rachel Elkins (California).

While the OREI project is generating some promising results, the report notes that the research project will not be completed until 2015.

“The interim year between approved antibiotics sunsetting and release of the OREI project findings leaves growers with minimal guidance and experience for non-antibiotic fire blight control,” said Jessica Shade, director of science programs for The Organic Center. “It’s unfortunate timing, as organic apple and pear demand are at all-time highs. If U.S. production declines, organic apple and pear prices could spike, or imports from South America — where the disease is not present — could greatly increase.”

In 2015, Shade said growers will be able to combine recommendations made by OSU and information provided by The Organic Center to get the most up-to-date picture of the status to control fire blight without antibiotics.

According to the report, there will be limited research results available between now and the October phaseout. “For the most part, in the single remaining fire blight season (spring 2014), each organic tree fruit grower will be the prime researcher on their orchard blocks in terms of testing and evaluating the best integrated systems approach to controlling fire blight without antibiotics,” the report stated.

Suggestions for fungal control, insect control, bloom thinning, spray coverage, tree training, soil and foliar nutrients, and cultivar and root stock selection are discussed in the report. “And, it provides detailed considerations for each stage of apple and pear production,” The Organic Center said in a press release announcing the report. “Some of the research is now validating the grower practices, such as the fire blight control from lime sulfur blossom thinning sprays.”