Spray Guides

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.

Midwest Fruit Pest Management Guide 2023-2024
(Hard copies of the Midwest Fruit Pest Management Guide are available for purchase ($15) through Purdue Extension)

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.

FRAME Fungicide Resistance Dashboard

FRAME Interpreting FRAC 11 Fungicide Resistance Tests and Powdery Mildew Resistance Management for Grape

Pesticide Stewardship of Speciality Crops: Train-the-Trainer Manual

Fungicide Resistance Action Committee (FRAC) website and FRAC Code List (2020)

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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