University of Maryland Extension

Bacterial Leaf Spots of Houseplants

bacterial spot dracaena

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There are several species of bacteria that attack houseplants. Some of these bacterial infections become systemic throughout the plant while others will remain as localized lesions. Bacterial disease symptoms range from black to brown, often watery leaf spots or lesions to total collapse of the tissue. Collapsed tissues usually are soft and mushy with a rotten smell to them. Leaf symptoms will often be observed between the veins and may be contained between leaf veins and appear angular or V-shaped. Some plants will characteristically develop lesions along the leaf margins where the bacteria enter through hydathodes (small openings along the leaf margins). Often these infections will cause leaf drop. Other symptoms may include yellow margins around leaf lesions, small blister like spots that run together, or spots where the center falls out.

Management Strategies: There are no cures for systemically infected plants and these plants should be discarded. Individual leaves with spots can be picked off and destroyed. Any method that will lower the humidity, decrease leaf wetness or increase air circulation will help to lessen the chances of infection. Watering should be done early in the day to allow leaf surfaces time to dry quickly. Space plants so that air can circulate between them to help reduce moisture. Registered pesticides containing copper can be used, but in most home conditions, removal of infected plant parts and adjustment of environmental conditions to drier conditions should help.

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