Brown Leaves on Chinese Evergreen Plants

Nematodes

• Parasitic nematodes are small soilborne, wormlike creatures that feed on living plant tissue, some from the plant’s above-ground parts and others from within root systems. Foliar nematodes do both and can affect Chinese evergreen plants. In addition to visible decline of the plant, the appearance of brown lesions on the leaves is a telltale sign that nematodes are present. Because prevention is easier than cure, it’s important you use only a sterile potting medium for container-grown plants.

Bacterial Diseases

• Leaf blight is caused by bacteria that gain entry into plant tissue through an open wound or through the stomata, the porelike surface openings through which plants conduct air exchange. This is a fairly common disease in houseplants, including Chinese evergreen. Symptoms begin as small dark green lesions developing along leaf edges, which eventually turn yellow and then brown when the infected plant tissue dies.

Leaf Spot Diseases

• Chinese evergreen is also vulnerable to bacterial leaf spot, caused by the bacterium Pseudomonas cichorii. As with other bacterial leaf diseases, lesions appear on infected leaves that at first may look like regions of light and dark shading or they may be brownish-black in color. The distinguishing feature of this disease is a yellow halo that typically forms around leaf discolorations.

Environmental Causes

• Although Chinese evergreen thrives in low light, it’s important the plant’s foliage isn’t exposed to direct sun or its leaves may burn and turn brown around the edges. Lower leaves of the plant may also turn brown and drop if you’re not watering it regularly. Too much fertilizer can also cause leaf burn and discoloration. The plant will suffer damage if exposed to temperatures lower than 50 degrees Fahrenheit, so if you live in a region outside of USDA zones 10b or 11 remember to bring plants inside when temperatures drop.