Leaf spot of Peach and Nectarines

Leaf spots on peach trees may indicate bacterial spot, a serious disease affecting peach and several related fruit trees. This disorder is most common in warm climates with high humidity and annual rainfall greater than 20 inches. Bacterial spot can damage and defoliate trees, and significantly reduce the quality and quantity of the crop they produce.
Symptoms. Bacterial spot appears as small, irregular spots or blotches on the leaf surface. These spots are usually deep purple, black or rusty brown, eventually tearing away and leaving a series of ragged holes in the leaf. After a while, the leaves turn yellow and drop prematurely from the tree. Small black or olive-brown spots may also appear on the fruit itself. These spots are most common on the side of the fruit facing the sun and they typically have water-soaked margins and a sunken appearance. Bacterial spot usually infects the tree's twigs as well, causing dark water-soaked blisters.