Field hygiene measures and resistant varieties against apple scab exist but if resistance is overcome, direct control with plant protection products is still the most efficient measure in organic production.
Solution
Based on the pathogen biology, local meteo data, forecasts and crop info, decision support systems, e.g. RIMpro or Simscab, enable farmers to assess the infection risk for apple scab and allow optimal timing of direct crop protection measures.
Description
Support systems such as RIMpro provide forecasts of infection events and assist farmers in the decision-making for higher efficacy of the treatments and better scab control.
Practical recommendation
Apple scab sprayings
• Preventive treatment prior to infection period: The freshly germinating ascospores are very susceptible to contact fungicide, so a preventive treatment can be implemented prior to spore ejection (Fig. 1, A).
o Until balloon stage (BBCH 59): copper (150-300 g pure copper/ha*) or copper + wettable sulfur (ex-change sulphur with a wetting agent when the temperature is low2); reduce the amount of copper as you get closer to the pre-bloom (risk of russeting).
o From balloon stage (BBCH 59) to walnut stage (BBCH 74)1: acidified clay mineral (8 kg/ha*) + wettable sulfur (8-12 kg/ha prior to full bloom BBCH 65, 3-8 kg/ha after full bloom, choose lower dosage if high temperatures*), or only wettable sulfur if acidified clay mineral is not allowed in your country*.
o From walnut stage on (BBCH 74): continue with acidified clay mineral + wettable sulfur*, or switch to copper (+ sulfur)*.
• Stop-treatment onto wet foliage: The amount of germinating ascospores over time is indicated by the white area behind the yellow bar (Fig. 1, 7). Within this time, a stop treatment can be used to kill the spores (Fig. 1, B).
o lime sulfur (25.6 l/ha prior to full Bloom, 19.2 l/ha after full bloom*) or
o potassium bicarbonate (4.8 kg/ha*) + wettable sulfur (8-12 kg/ha prior to full bloom BBCH 65, 3 8 kg/ha after full bloom, choose lower dosage if high temperatures2*)
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When you activate this function, your browser establishes a direct connection with the servers of the third-party provider. We would like to point out that data is transmitted to the third-party provider after activation, and the latter may set cookies that can also be used for analysis and marketing purposes. For more information, please refer to our privacy policy.
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