Please contact Dr. Melanie Lewis Ivey if you have any questions about the material provided in the spray guides. Any fungicide recommendations included in the OSU guides are specific to Ohio and only guaranteed to be valid for the year that the guides were published. Always consult the fungicide label to confirm that recommended fungicides are still registered for use in Ohio.
OSU Blueberry Spray Guide 2017
OSU Grape Spray Guide 2020 2019 2018 2017
OSU Hop Spray Guide 2020, 2019 2018
Strawberry Spay Guides Kentucky State University Small Fruit Consortium 2020
Midwest Fruit Pest Management Guide 2021-2022
Fungicide Resistance Management
A spray program should be thoughtfully developed to prevent and slow the development of fungicide or antibiotic resistant pathogens in the planting. In addition to the information on fungicide resistance in the OSU spray guides the following resources are available on fungicide and antibiotic resistance.
Antibiotic Resistance Management
Antibiotics are used for the management of only a few bacterial plant diseases due in part because of the expense involved. Antibiotics, specifically streptomycin, represent the best option for fire blight of apple and pear control. However, in crop production systems where antibiotics are used multiple times in a season and over many seasons, antibiotic resistance can be a problem. Antibiotic resistance evolves in bacteria through mutations in target-site proteins or through the acquisition of antibiotic-resistance genes. The ability of bacterial pathogens to acquire antibiotic-resistance genes has resulted in reduce control of crop diseases as well as issues that affect successful treatment of some specific human bacterial infections. In 2018, strains of Erwinia amylovora (the cause of fire blight) resistant to streptomycin, were detected in Ohio apple orchards. Orchards with strains of streptomycin resistant Erwinia amylovora should reduce or eliminate the use of streptomycin for fire blight management. Alternatives to streptomycin include kasugamycin and oxytetracycline. In addition, antibiotics should only be applied during the bloom period. Antibiotics applied to shoots will not be effective at controlling fire blight and will increase the risk of resistance development in the pathogen. For more information on how to slow or prevent antibiotic resistance development in E. amylovora please contact Dr. Melanie Lewis Ivey or your county Extension Educator.
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