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Leaf Spot

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Caused By:-     Various Fungi and Bacteria

Description

Leaf infections called "leafspots" are caused by a variety of fungi and some bacteria on many trees, shrubs and perennials. There are basically two types of leaf spots one caused by fungi and another caused by bacteria. A leaf spot diseases causes spots to appear on the foliage. The spots will vary in size and colour depending on the plant, the organism involved and the stage of development. Spots are most often brownish, but may be tan or black. They usually start of as necrotic spots. Positive identification usually requires laboratory diagnosis, but bacterial leaf spot often have a halo of lighter colour around the spot and there are no raised fruiting bodies (picnidia or spore producing bodies) in the spot as is often the case with fungal leaf spot. Fungal leaf spot can merge together forming large patches of dead foliage. The leaves may turn yellow and drop prematurely. In most cases, leaf spot is considered to be only a cosmetic problem, but they can have economic effects on nurseries or flower production. Leaf spot is often an indication that the plant or tree is suffering from inadequate growing conditions or suffering from other diseases which is putting the plant under stress.

Control

If leaves are severely infected they can be pruned out and fallen leaves raked up and destroyed. Fungicides or bactericides can be used, but they must be used before the build up of the pest. Avoid overhead irrigation as this tends to aid the pests development if the water is on the leaves for any length of time. Good growing conditions and husbandry is essential to avoid these problems. Prune the tree or plant to allow good airflow through the leaves.

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