![]() ![]() ![]() In general, the foliage becomes dull and grayish, ultimately resulting in scorched or dried leaves. Symptoms on ivy geraniums are much less obvious than those that occur on seed and zonal types. Other bacteria may cause similar spots but do not result in wilt. The bacterium will move into the vascular system of the leaf and then into the stem. Leaf spots are soon accompanied by yellowing, often in a V-shaped pattern. They may be circular or they may run together resulting in a blighted appearance. When leaves are held up to the light, the spots will have dark centers with translucent borders. For leaf spot to develop, the bacterium has to be splashed from one plant to another or be underneath hanging baskets that are contaminated. Leaf spot is less common than wilt but may occur if plants in advanced stages of disease are present. Excessive fertilizer can also mimic these symptoms. However, if root rot is evident, that does not rule out the presence of bacterial blight. In greenhouses, the most common symptom is a wilting of one or more leaves even though the root system appears healthy and the soil is moist. The stem rot phase is occasionally referred to as black rot and can be confused with the black leg disease caused by the fungus Pythium. Leaf spot and stem rot may or may not occur. The bacterium reproduces and moves systemically in the water conducting cells of the plant resulting in wilt. Plants suspected of having bacterial blight should be examined by a plant pathologist. Geranium producers should be aware of the symptoms and its diagnosis. Bacterial blight is not as common as other geranium diseases but cases occur every year, occasionally in epidemic proportions. Ivy and seed geraniums are also susceptible while "Martha Washington" is not. pelargonii, is the most serious disease of the florist's geranium. Bacterial blight, caused by Xanthomonas campestris pv. ![]()
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