Brown Bumps on Ficus Tree

Causes

• Fungi and bacteria can cause brown spots or lumpy masses to appear on the leaves and wood of ficus trees. Insects such as armored scales appear as tiny tan, dark brown or black bumps lining the branches and twigs of the tree. Edema, which is a problem resulting from too much water in the tree's environment, also can cause brown spots to appear on the leaves.

Symptoms

• Anthracnose is the common name for a group of fungi that attack ficus trees, and Ficus elastica cultivars in particular. The fungal spores spread on water and first appear as small yellowish spots on the leaves, later darkening to brown. They are not usually raised. Botrytis cinerea is another fungus that causes large, flat brown spots to appear on the leaves. Bacterial diseases usually present as raised, bumpy masses called galls. These brown bumps may be small or up to several inches in diameter. Scale are tiny, but still easily visible, light or dark brown insects with smooth, oval shells. These sap-sucking insects cling tightly to the wood and to the undersides of the leaves. Edema appears as brown, water-soaked lesions on the leaves. They may also look like piece of cork.

Treatment

• Fungal and bacterial diseases have no cure once the symptoms appear. If the symptoms are limited to one area of the tree, prune off the affected branches to prevent the disease from spreading to the rest of the tree. Fungi and bacteria differ in their seriousness. Some, such as Agrobacterium tumefaciens, or crown gall, necessitate complete removal of the tree, according to the University of Florida website. Others are unattractive but do not pose a health threat. Scale can be manually removed by scraping them off with a cotton swab dipped in alcohol, or even with your fingernail, but this is not always practical on large trees. In the case of the latter, spray the tree with an insecticide. Follow the directions on the bottle as per the size and age of your tree, and repeat the application after about two weeks. Adding liquid soap to the insecticide can help make it more effective, because that will help it penetrate the insects' shells. If your tree is suffering from edema, let the soil dry out to the touch before watering the tree again, and ensure the area drains well or that the container has drainage holes.

Prevention

• Bacterial diseases spread on tainted tools or stock. Sterilize pruning and other gardening tools before using them, and while using them, especially if you are pruning off diseased wood. Dip the blade in a bucket of bleach before you make a new cut. This can also help prevent the spread of fungal diseases. Fungi thrive in wet conditions, so prune nearby plants so that your tree has plenty of room for air to circulate around it. In addition, always water at the ground level rather than from overhead to prevent water from sitting on the leaves. Gather up and dispose of infected leaves rather than letting them sit on the ground, so that the spores do not overwinter in the soil. Spraying your tree with fungicide in the spring can also help prevent fungal diseases. Scale often migrate from other plants, so keep an eye on other, nearby plants for signs of infestation. Edema can be prevented by not over-watering your tree. Ficus trees grow best in moist, but not overly wet soil.