| Abstract: | Phytophthora frugariae causes red core root rot of strawberries. Although the disease is probably most acute in northern Europe, serious outbreaks have been reported from a number of Mediterranean countries, especially France and Italy. Leather rot of fruit and crown rot, which are caused by P. cuctorum, can also be severe problems in warmer climates. Both fungi survive in soil for long periods, but the most common form of spread is in diseased planting material. Sensitive tests have been developed to detect red core in planting material, and been used to effect in certification schemes. Root rot of raspberry has gained prominence in the last 10 years in Europe as raspberry growing has expanded, but the disease has been known for many years in France. Nine species of Phyfophthora have been recovered from affected plants, but two of these, one with affinities with P. megasperma, and P. cumbiuora, are responsible for most major outbreaks. The other species are only troublesome where drainage is poor. Again, spread is mainly in infected material. Few raspberries are resistant to root rot, but some wild RubuP spp., blackberries and raspberry x blackberry hybrids are resistant and may be useful in breeding programmes. |
