Cider fruit production is threatened by the bacterial disease fireblight, caused by Erwinia amylovora. Fireblight is a notifiable, highly contagious disease. After severe outbreaks in 2007 and 2012 with economically large losses, the demand for solutions was accordingly high. From 2008 till 2015, the use of the antibiotic streptomycin against fireblight was locally and temporarily limited allowed, however only under strict conditions. It was clear, that this can only be a temporary solution. Hence, in 2012 was the kick-off for the three and a half-year project HERAKLES. The project, conducted at Agroscope in Wädenswil, focused on three approaches for a sustainable fireblight management: robust varieties, effective crop protection and adapted cultivation methods.
In crop protection trials in the project HERAKLES, strategies with the products LMA, Vacciplant, Blossom Protect and Myco-Sin were tested for integrated and organic farming. None of these strategies could keep up with the high efficiency of streptomycin.
It is therefore all the more important to include fire blight robust varieties as a key-factor for a holistic fire blight management.
In shoot inoculation tests with artificial fireblight inoculation in the greenhouse, 59 apple and 45 pear varieties were tested. In the field, 39 apple and two pear varieties were tested for their susceptibility to fire blight by artificial flower inoculation. In each test almost half of the varieties proved to be at least "low" susceptible to fire blight, including nine apple varieties with the rating "very low" in both tests.
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