The genus Ficus contains some of the most durable plants you can grow and are known for their glossy, leathery leaves. Each species within this genus varies in growth habit, height, and leaf shape and size, but all are susceptible to molds caused by a variety of fungi. In most cases, proper cultural practices such as ensuring your plant has good air flow, and preventing insect infestations and wet foliage can prevent mold from forming.
Sooty mold (Capnodium spp.) is a common name for several fungi that grow on the secretions of sucking insects such as scales, psyllids and aphids. These pests secrete a sticky substance called honeydew, upon which a black or grayish mold develops. This fungus looks like soot, but it only grows on the surface and does not infect plants. The problem with sooty mold fungus is that it reduces sunlight penetration, which can lead to stunted growth and reduced vigor. Prune affected parts, and rinse your ficus plant with a strong spray of water weekly to remove pests and clean the leaves. Several insecticides and horticultural oils are labeled for use on pests that secrete honeydew. When selecting a product, read the label directions carefully and make sure the product is safe to use on ficus species.
Anthracnose infections in ficus plants are caused by the fungi Glomerella cingulata and Colletotrichum gloeosporoides. Symptoms show on leaves as slightly sunken areas surrounded by a dark brown border. These areas eventually dry out along the margins and fall off. The fruit also develops small, discolored, sunken areas that develop pink spore masses in the center. To control anthracnose in ficus plants, remove fallen and infected leaves and fruits to prevent reinfection. Applications of mancozeb fungicides can prevent spread of anthracnose to healthy leaves.
Aerial Blight, Web Blight
Aerial blight or web blight is caused by the fungi Thanatephorus cucumeris and Rhizoctonia solani. Symptoms begin as yellow or brownish areas on the leaves that may appear water-soaked. The upper leaf surface later turns silver-white, and the underside is covered with brown webbing. Infected leaves die, but may be held on the twigs by fungal strands called mycelia. These strands can cover and kill twigs, and may cover fruit, resulting in fruit mummification. Tiny brown to black reproductive structures present on the fungal strands are resistant to unfavorable environmental conditions, allowing the fungus to survive for long periods on the plant, in the soil and on plant debris. Control spread of infection by pruning to allow air circulation around the foliage and avoiding overhead irrigation. Remove all diseased or fallen leaves to prevent spread of the infection. Soil applications of fungicides containing Pentachloronitrobenzene, also called quintozene, may be effective in controlling severe infections.
Pink Limb Blight
Caused by the fungi Erythricium salmonicolor and Corticum salmonicolor, pink limb blight attacks limbs, twigs and trunks of fig plants. Symptoms of infection include a pale pink mycelium that usually encircles plant tissue. The leaves on infected branches wilt and die, and eventually the entire limb or twig may die. To control pink limb blight, remove infected parts immediately, cutting at least 4 to 6 inches below mycelium-covered twigs. Destroy all pruned material to prevent spread of infection to healthy plants.
- University of Florida IFAS Extension: Florida Plant Disease Management Guide: Fig (Ficus carica)
- University of Minnesota Extension: Rubber Trees, Weeping Figs and Other Friendly Ficus
- Hortica Publications: The Basics of Foliage Diseases
- Penn State Extension: Ficus Diseases
- UC IPM Online: Floriculture and Ornamental Nurseries: Management of Soilborne Pathogens
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