Scab fungi, including Venturia pirina, belong to one of the key parasites in fruit cultivation. When no control measures are implemented, the pathogen can cause complete damage to the harvest in favorable weather conditions. Scab poses a major challenge in the organic cultivation of pears. Depending on the cultivar, it is possible that twig scab develops during time. This source of infection makes scab more difficult to control, as fruit growers must consider secondary infections through conidia from the beginning of the season. Once twig scab is present in the orchard, achieving  profitable organic production becomes a major challenge with the currently available products.

During the last years, Europe has increasingly emphasized sustainable agriculture. The organic fruit growers in Flanders could have more possibilities if there was a better control of scab in pear. The use of products that induce the plant defence, the so called Plant Defence Enhancers or PDE’s, can offer a solution.

The objective of this project is to make the control of scab less dependent of copper and sulfur, strengthen the range of possible control measures and gain deeper insights in the origin and expansion of the disease.

For this purpose, the scab situation will be monitored in a few orchards with varying scab pressure, whether or not after the artificial inoculation and after the application of PDE’s on different moments during the season (primary scab period, secondary scab period and after harvest), taking into account the climatological conditions. Both symptoms as molecular analyses will be used to determine which leaves are most sensitive to scab. A V. pirina specific qPCR (quantitative PCR) will be developed to track the scab development on leaves and fruits at early stages of infection before visible symptoms appear. Furthermore, the transcription of selected genes involved in the defense response of the plant will be monitored after the application of PDE’s.

Based on the acquired knowledge, we want to provide clear recommendations for the control of scab through a system-based approach in the organic production of pear and to validate this under practical conditions.