Fruit trees are tender, deciduous trees. Collectively, these fruit-bearing trees are susceptible to a number of diseases, many of which target the foliage tree. Although some of these leaf diseases cause only cosmetic effects, some can have detrimental effects on the fruit tree when left untreated.
Peach Leaf Curl
Peach leaf curl is a disease specific to peach trees. This fungal disease causes the leaves of the peach tree to produce and grow more rapidly than normal. The infected leaves develop thickened, reddish areas that eventually cause curling and distortion of the leaves. The infected foliage experiences a yellowish discoloration that turns white as the leaves begin to die. The disease also affects the twigs and shoots of the peach tree. These infected areas experience growth stunt and dieback as they become thickened and distorted. Peach leaf curl can be treated with a combination of pruning and copper-based fungicidal treatments.
Alternaria Leaf Blotch
Fruit trees that have been infected with alternaria leaf blotch will develop lesions on their foliage during the late spring. These lesions appear as small, dark-colored spots that enlarge as the disease progresses. The lesions are pronounced with dark purplish colored margins. Fruit trees that are severely infected with alternaria leaf blotch will experience premature defoliation of most, if not all, of their foliage. Heavy defoliation of the fruit tree causes growth stunt, dieback and reduced fruit production during the following year's growing season. Pruning of the infected areas is required to control the disease. Pruning should be combined with a fungicidal treatment to reduce the potential of further infection.
Powdery mildew is a common fungal disease that targets the young, tender foliage of the fruit tree. This disease is transported by fungal spores that germinate on the old, defoliated debris that lies around the tree. Initial infections cause the formation of small, dark-colored foliage spots that are accompanied by a powdery white mildew. As the disease progresses, the surfaces of the foliage become covered with this white mildew which hides the necrotic areas on the leaves. Powdery mildew is easily treated by pruning away the infected areas and treating the fruit tree with a fungicidal spray.