Effective Management for Fire Blight for Sustainable Apple Production in Illinois

Effective Management for Fire Blight for Sustainable Apple Production in Illinois

Summary

More than 300 growers manage approximately 5,000 acres of apple orchards in Illinois. Illinois with a population of 13,000,000 is a huge market for apples, particularly for the rapidly growing “You Pick” operations. Fire blight, caused by the bacterium Erwinia amylovora, is a serious threat to apple production in Illinois and other Midwestern states. Apple trees are most vulnerable to fire blight infection at bloom. Streptomycin has been the most effective chemical for control of fire blight of apple and other pome fruits. However, streptomycin-resistant (SmR) E. amylovora populations have been reported from several apple growing states. Widespread and severe fire blight occurred in Illinois apple orchards in the past five years leading to speculation that SmR strains of E. amylovora may have developed in some orchards in the state. No previous study has been conducted in Illinois to determine the presence of SmR bacterium in the state. Since, streptomycin is the most effective antibiotic for control of fire blight of apple, it is necessary to identify cases of antibiotic-resistance early, before resistant strains become widely established. The main goal of this research is to determine if streptomycin-resistant E. amylovora exist in Illinois and develop alternative control measures for the pathogen. The specific objectives of this study will be to: (i) evaluate Illinois E. amylovora populations for streptomycin resistance, and (ii) evaluate streptomycin alternatives, including kasugamycin, oxytetracyline, copper compounds, and bio-control agents for management of fire blight. The results of the research will be published in the newsletters, bulletins, and websites; presented to the growers, Extension educators, and agribusiness in winter growers’ schools and summer horticulture days; and published in peer-reviewed journals such as Plant Disease and HortScience.

Objectives/Performance Targets

The main goal of this research is to determine if streptomycin-resistant E. amylovora exist in Illinois and develop alternative control measures for the pathogen. The specific objectives of this study will be to: (i) evaluate Illinois E. amylovora populations for streptomycin resistance, and (ii) evaluate streptomycin alternatives, including kasugamycin, oxytetracyline, copper compounds, and bio-control agents for management of fire blight.

Accomplishments/Milestones

The results of this research will be transferred to growers using the following approaches. Meeting Presentations: the results will be presented to growers and Extension personnel in the local, statewide, and regional winter school meetings. Field Day Meeting: the results will be showcased to the growers and Extension educators in the Illinois Summer Horticulture Day meeting, which is held every year in the second week of June. Newsletters and bulletins: the goals and results of the project will be published in the newsletters and bulletins and posted on the Internet. Also, results of this study will be published in refereed journals

Impacts and Contributions/Outcomes

Short term outcome of this project would be determining whether or not streptomycin-resistant (SmR) populations of Erwinia amylovora are present in Illinois apple orchards. The intermediate and long-term objectives of this study will be effective use of streptomycin and developing alternatives to streptomycin, including kasugamycin, oxytetracyline, copper compounds, and bio-control agents for management of fire blight. Results will be used to develop effective IPM strategies to avoid/delay occurrence of SmR E. amylovora in Illinois and neighboring states.

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