Diseases of Ficus Elastica

Plant Pathogens

• Overwatering and splashing water provide the perfect environment for bacterial and fungal diseases to attack Ficus elastica. The plant is susceptible to root, stem and crown rots as well as leaf spots, wilt and bacterial blights caused by a variety of pathogens. Bacterial diseases caused by Erwinia carotovora subsp. carotovora and Erwinia chrysanthemi, Xanthomonas and Pseudonomoas thrive in moist, warm conditions and may travel via infected pruning tools, splashing water and gardening gloves. These pathogens affect the foliage and can cause the stems to rot and die. Treatment depends on the pathogen. The Cooperative Extension Service office may be able to diagnose the pathogen at little to no cost.

Foliar Nematodes

• Ficus elastica is especially susceptible to foliar nematode (Aphelechoides), which causes areas between the leaf veins to turn yellow. The leaves may die. Cut off and destroy infected leaves if the infection is mild. Throw the ficus away and start over if the plant is severely infected. Nematode treatments are generally ineffective at controlling this pest.

Insect Vectors

• Scale insects such as brown soft scale (Coccus hesperidum), hemispherical scale (Saissetia coffeae), mealybugs and whiteflies can infest rubber tree plants. The insects exude a sticky substance called honeydew that provides a growing base for black or sooty mold fungus. Wipe the plant's leaves with alcohol or soapy water to clean off the honeydew and remove the insects. Insecticidal oils can suffocate the insects. Pesticide sprays containing permethrins may be effective, but they must be reapplied weekly until the insects are gone. Systemic insecticides containing imidacloprid may control large infestations of soft-scale insects.

Disease-Mimicking Conditions

• If the Ficus elastica's leaves develop large brown blotches, the cause may not be disease. The plants do not like cold air, and young leaves become deformed and brown if the plant is situated near air-conditioner ducts or suffer temperatures below 40 degrees Fahrenheit. Nutritional deficiencies can wreak havoc on the plant's foliage, causing chlorosis and leaf death. In most cases, the plant needs more potassium. Take a sample of the affected tissue to your area's Cooperative Extension Service office for analysis and information on how to correct nutritional deficiencies.