The corn stalk houseplant (Dracaena fragrans) is a favorite with indoor home gardeners for its general hardiness, tall form and ability to grow even in low light conditions. While this adaptable "Chinese evergreen" is tolerant of different types of soil and periods of drought, the plant can suffer from root rot and leaf spot diseases, according to the University of Florida. Corn stalk houseplants can also appear to be suffering from a deadly disease when they are exposed to too much fluoride.
Root rot is the most common disease affecting houseplants, according to Purdue University. Overwatering keeps the soil cool and moist, which is the perfect environment for the fungi that cause root rot to develop. These fungi enter the roots through the fine hair roots and work their way up to the larger roots and sometimes the stem as well. The roots become ineffective at absorbing nutrients, and the plant wilts. In time, the plant will die.
Once symptoms are noticed, the roots may be too damaged to save the corn stalk plant. Avoid root rot by taking care not to overwater your dracaena, and always use clean, sterilized potting soil.
Several different types of water-borne fungi cause leaf spot. The disease manifests as spots on the leaves, which can vary in color and size. Some are tiny and black, while others are large with a halo or border. In severe cases, the spots may merge. Affected leaves may turn brown, shrivel or curl up or even drop from the plant.
Prevent leaf spot by making sure you purchase healthy plants. Avoid misting your corn stalk plant too often, as this will leave water sitting on the leaves. Pick off affected leaves and discard them, and make sure there is room for air to circulate around the plant. Finally, if your plant is infected, move it away from other, healthy plants to prevent the fungi from spreading.
Corn stalk plants are quite sensitive to fluoride, according to Clemson University. Too much fluoride in the water will cause disease-like symptoms to develop, including yellowing or browning of the tips of the leaves, or the development of dry, dead areas. Avoid using superphosphate fertilizer, which contains high levels of fluoride, and water with distilled water. In addition, do not use potting soil that contains a large amount of perlite.