Ficus benjamina is also known as the weeping fig, Benjamin fig or simply as a ficus plant. It is an evergreen species that can grow into a tree up to 100 feet tall, but is most often grown as a house plant. While mostly problem free in cultivation, it is vulnerable to several pests and diseases that are easiest to treat if recognized early. Many diseases of ficus plants are due to the plants growing in conditions that are not suited to the species. Avoid watering ficus plants from above as they are vulnerable to fungal disease caused by wet leaves.
Ficus plants are vulnerable to fungal diseases such Botrytis cinerea, which is most common on grape vines. Infected plants will have brown or black spots on the leaves. Any infected leaves must be removed and the whole plant treated with a fungicidal spray. Infected plants should also be isolated to prevent the disease spreading to other plants. Ficus plants that are over watered or kept in damp conditions are most vulnerable to fungal disease.
Crown gall, Agrobacterium tumefaciens, is a bacterial disease that causes swollen stems, leaf veins and roots that become "corky" with time. The main point of infection is often the crown where the main stem joins the roots. While the disease is not fatal it can cause serious disfigurement of ficus plants and can be spread to other plants by dirty cutting tools.
Phomopsis is a fungal infection that causes ficus plant leaves, roots and stems to die back and can even kill whole plants. A ficus plant infected with phomopsis will have dead drown leaves and twigs that do not drop off the plant. Plants that have been extensively pruned are most vulnerable. The infection can be passed from plant to plant by hedge trimmers or dirty garden knives or scissors, according to . Isolated infected plants and sterilize all garden tools before using them on other plants. Phomopsis can be treated by pruning any infected parts of the plant with sterile tools.
Anthracnose is a fungal infection of ficus leaves caused by the fungus Glomerella cingulata. It manifests as yellow spots on the leaves that turn brown and become sunken. Infection eventually covers and kills whole leaves. Move infected plants to a dry location and reduce misting and watering. A copper-based foliar fungicide will prevent the disease from spreading.
Ficus plants are susceptible to infection by Xanthomonas campestris bacteria. The first symptoms are the appearance of tiny wet paches on the leaves which grow and turn brown with a yellow fringe. Tretament is with a copper-based bacteriocidal spray and the removeal of branches with infected leaves.
Scale insects are small, immobile insects that tend to cluster on the undersides of leaves or on new growth stems and shoots. They are up to 1/8 inch long and look like small, brown or yellow bumps. Mealy bugs are similar to scale insects but protected by a coating of fluffy white threads. Both types of insect pests are vectors for viruses that can infect and disfigure ficus plants. They alse exude a sweet liquid onto the surface of their host plants which can encourage the growth of sooty mold.