In 2011, when the National Organic Standards Board made a formal recommendation to the National Organic Program to permit oxytetracyline for fireblight control in apples and pears only until October 21, 2014, the board stated the following:
That its Crops Committee was presented with evidence that tetracycline antibiotics can contribute to antibiotic resistance in human pathogens when used as pesticides on plants.
Evidence the board cited included:
—A 2010 study of tetracycline resistance in Salmonella strains recovered from irrigation water in Mexico
—A 1976 report on changes in intestinal flora of farm personnel after introduction of a tetracycline-supplemented feed on a farm
—A Wikipedia article about tetracycline
—A Proposition 65 materials list from the California Office of Environmental Health Hazard Assessment
That additional products are available for use against fireblight, such as Serenade Max, Bloomtime Biological FD, BlightBan C9-1, and Blightban A506.
Literature cited were:
—A 2007 article on using Pseudomonas spp. for integrated biological control by Dr. Virginia Stockwell at Oregon State University, which discusses how Blightban506 can be used in combination with antibiotics to control fireblight
—“Fireblight: the search for better control,” a 1998 report in which Dr. Herb Aldwinckle at Cornell University, New York, stated that, “There is no single control measure for fireblight that will totally eradicate the disease, provide an absolute cure, or fully protect an orchard. However, by integrating several orchard management practices, fireblight damage can be kept to a minimum. These practices include orchard site selection and maintenance, tree selection and nutrition, soil management, and chemical control measures.”
—An article on fireblight management by Tim Smith, Washington State University Extension specialist, who stated that, “To date, researchers have shown that biological control agents provide partial reduction of blight infection, as high as 50-85 percent in field tests, and even higher in the laboratory. If applied two or three days ahead of an actual infection, this 50-85 percent control will be in place when the more effective control product, usually an antibiotic, is applied.”
That Surround (kaolin clay) has had some success in controlling fireblight.
In his 2004 report of a trial investigating the effects of Surround on fireblight, Chuck Ingles, with the University of California Extension, stated that, “Although the incidence of fireblight was not substantial, less blight was found in blocks that were treated with Surround. However, it is not possible to say conclusively whether or not Surround would reduce blight incidence in years with greater blight pressure.”
In its recommendation, the NOSB stated:
“Given the public health threat associated with antibiotic resistance, there is a history of board and public concern that organic production not contribute in a small or large way to antibiotic resistance. The (crops) committee originally passed a motion denying the petition, but based on comments that more time is needed to make a transition, proposed that the expiration date be postponed until October 21, 2014. The committee feels antibiotic resistance in human pathogens is an issue that should drive a process to speedy adoption of alternative management of fireblight.”SOURCE: Formal recommendation by National Organic Standards Board to the National Organic Program on the tetracycline petition, dated April 29, 2011, available at the Web site www.ams.usda.gov/AMSv1.0/ under National Organic Program, National Organic Standards Board, Recommendations.