This fungus infects Ribes leaves, shoot tips and on some species, eg. R. grossularia in severe infections, the fruit as well, rendering it useless. First recorded on gooseberries in Ireland in 1900, it spread to epidemic proportions throughout Europe by the 1960s on both gooseberries and blackcurrants. For older susceptible Ribes cultivars, especially of gooseberry, mildew remains the major limiting factor to successful cultivation. Control of mildew on susceptible cultivars is dependent on frequent fungicide applications, and the development of resistant types is a breeding objective in most modern Ribes programmes. Modern cultivars that are resistant to mildew include 'Ben Alder', 'Ben Tirran, 'Ben Hope, 'Ben Gairn and 'Ben Dorain'. S. mors-uvae produces new races that can often overcome resistance; for example, the cultivar 'Ben Lomond' was resistant when released in 1972 but is now completely susceptible. However, other cultivars have remained resistant for over 50 years, with the resistance attributed to epidermal cell developmental factors.
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| Blackcurrant mildew |
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