Philodendron Diseases

Leaf Spot

• Different types of bacteria can cause leaf spot on a variety of plants. In philodendrons, Xanthomonas makes its appearance by showing a reddish discoloration in leaf margins. Pseudomonas emerge as dark, water-soaked areas that soon turn brown or black, often with yellow rings around the spots. The best defense against leaf spot is to examine plants carefully before bringing them home. Also, buy from a reputable commercial grower. Once at home, take care not to over water plants, and use a watering can with a long spout to wet only the soil, not the leaves. Also, avoid overcrowding plants and do not place them in heavily shaded areas or in spots where air circulation is poor.

Bacterial Blight

• One sign of bacterial blight is small, dark green spots on philodendron leaves. These blemishes can spread to the leaf stalks, and if left untreated, leaves will eventually rot and die. The best way to prevent bacterial blight is to avoid getting the leaves wet. Remove infected leaves immediately. To combat bacterial diseases such as leaf spot and blight, a streptomycin-based formula can be applied when symptoms first appear. As with any chemical spray, always follow the directions on the manufacturer's label.

Magnesium Deficiency

• A philodendron experiencing magnesium deficiency will show V-shaped yellow spots on its leaves. This problem usually occurs in greenhouses, where the temperature is cool. To rejuvenate the plant, add 1 tsp. of magnesium sulfate per gallon of water and apply to the soil.

Tip Curl

• Not all plant diseases are caused by bacteria -- caregivers' actions sometimes contribute to a plant's sickness. Over fertilizing can cause tip curl. As the name implies, leaf tips curl down and turn brown, and if the problem is not corrected, the roots may die. If a philodendron shows signs of tip curl, leach the soil immediately. If a slow-release fertilizer has been used, leaching may need to be repeated. Take care in the future to fertilize according to the instructions on the package.