What is special about pear scab (Venturia pirina)? (BIOFRUITNET Practice Abstract)

The right knowledge and strategy will benefit growers specialised in pear, a minor crop compared to apple. Practical recommendation Although ascospores and conidia (twig scab) can be in the orchard, it is essential to reduce the amount of ascospores in spring. There is no specific decision support model for pear scab. Preventive measures to reduce inoculum and the risk of infection (ascospores) • Stimulate leaf decomposition using vinasse in autumn at leaf fall • Reduce the amount of fallen leaves in autumn and winter by machinery for shredding or removing leaves • Avoid overwintering leaves in neighbouring land, hedges or bushes • Prune away shoots with twig-scab in winter Preventive measures to reduce the risk of spore germination • Proper pruning for an open and fast-drying tree, to prevent too long leaf wetness • Avoid too much growth by root or stem pruning • Proper fertilisation • Choice of varieties. There is no resistance gene known for pear scab. Varieties with a low incidence of scab are Xenia, and Concorde. Varieties susceptible to scab are, for example Conference and Williams • Use models to predict infections • No overhead irrigation but drip irrigation Direct control • Before rain (preventive), during rain (stop-spray) or after rain (curative) • Plant protection products: copper, sulphur, lime sulphur and bicarbonates (when allowed