What Is the Orange Thing Hanging From My Cedar Trees?
- Cedar-apple rust is the cause of orange apple-sized lumps that grow on cedar trees. This is a fungal disease that attacks both juniper trees and apple trees. The fungus spends much of its life cycle living on cedar trees, which belong to the juniper family. The "apple" produced by the fungus is a spore-producing site that helps spread the disease to neighboring plants and trees that host it. Cedar-apple rust is a serious problem for trees.
- The cedar-apple rust fungus not only produces the orange "apple" that hangs from trees, it also covers branches in an orange rust-colored fungus that prevents the cedar tree from photosynthesizing. Cedar-apple rust also gets inside the cedar tree and weakens it over time, leading to vitiated growth and greater susceptibility to other fungal problems and pest insects. Eventually, cedar-apple rust kills a cedar tree if the fungus is left untreated.
- Remove branches affected with cedar-apple rust, especially those that exhibit the spore-producing "apple." Cut off branches close to the trunk of the tree and dispose of them to prevent the fungus from spreading. Keep the soil around the cedar tree from holding standing water, which promotes fungal growth. Plant cedar and apple trees far apart to prevent transferring the fungus from one tree to another, which is necessary for its life cycle to be successful.
- Fungicides are an essential factor in controlling the presence and spread of cedar-apple rust. Spray a fungicide in the early spring to control the release of spores, or use a dormant horticultural oil, depending on the needs of the tree. Apply fungicides throughout the growing season according to the directions on the fungicide to help keep the cedar-apple rust from maturing and spreading throughout the cedar tree and producing more spores.
