Comment submitted by Kent Evans, Ph.D., Utah State University, Extension Plant Pathology Program

I have personally documented the extent of resistance to currently available antibiotics (streptomycin and oxytetracycline) in Utah. At present, streptomycin is completely inadequate to control fire blight and there is a disturbing inability of oxytetracycline to provide adequate control of fire blight, either due to climatic or environmental effects that render it less effective to manage fire blight. Our trials in Utah, using Kasugamycin, have shown that the antibiotic is highly effective against Erwinia amylovora strains that are resistant to streptomycin. Our field trials have demonstrated that kasugamycin is highly effective to manage fire blight as well. It is my professional opinion that kasugamycin emergency use approval is needed to provide an option for growers of apples to rotate between oxytetracycline and kasugamycin to lessen the probability of developing resistance to our sole remaining antibiotic that is currently approved (oxytetracycline) that resistance is reported to occur in some areas of the U.S. (California, as it is the sole chemical approved as streptomycin resistance is documented there as well). I have attached a report of efficacy of kasugamycin in shoot strike and floral strike field evaluations. Sincerely, Kent Evans, Extension Plant Pathologist Utah State University Biology Department 5305 Old Main Hill Logan, UT 84322-5305