Phytophthora fruit rot was relatively unimportant until the 1970s when it emerged as an important cause of rotting in stored fruit in many countries in north-west Europe, with some batches of stored Cox with up to 88% rotting due to P. syringae in the 1974 UK harvest.
- Its emergence as an important storage rot followed the adoption of intensive systems of apple production using dwarfing rootstocks resulting in low-hanging fruit.
- The tree row in these systems is maintained weed-free by use of herbicide (herbicide strip), thus exposing the low-hanging fruit to the risk of soil splash.
- The rot is of sporadic occurrence associated with wet harvests but losses can be significant when weather conditions are favourable.