Peach vs Sour cherry

In Central Europe peach leaf curl (Taphrina deformans) appears every year: the emerging leaves thicken, blister, turn red and fall, and the tree weakens year after year. It can only be prevented: a copper wash before bud burst, then a systemic fungicide when the first tiny leaves show, repeated several times in a cool, wet spring; once curled leaves are visible it is too late. A sunny, airy site and a more resistant cultivar reduce the problem. Other troubles are powdery mildew (mainly on nectarines), shot hole, Monilia blossom and shoot blight and fruit rot, aphids, peach twig borer and oriental fruit moth, which tunnel in shoots and fruit, and plum pox virus. Flower buds are damaged by hard winter frost (roughly below minus 20 °C) and the blossom by spring frost. It fruits on the previous year's shoots, so it needs hard pruning every year (around flowering or in summer, not in winter) or it goes bare inside; the tree often declines after just 15 to 20 years, hastened by gummosis and branch dieback. Do not replant a peach in the same spot, and expect yellowing leaves (iron deficiency) on chalky soil.

In Central Europe the key problem of sour cherry is Monilia blossom and shoot blight: in a cool, rainy flowering period the blossoms turn brown, the twigs die back within days, and without control the crown becomes bare in a few years. Cut diseased parts back to healthy wood and spray susceptible varieties at flowering, or choose a more resistant variety. Cherry leaf spot (Blumeriella) can defoliate the tree by midsummer and weaken it. Cherry fruit fly (the European species and the later-flying eastern one) also infests sour cherries, and birds take part of the crop. It struggles on waterlogged, heavy and strongly acidic soils.