My Blue Spruce Is Turning Brown at the Tips

Spruce Needle Rust

• Spruce needle rust (Chrysomyxa ledicola Logerh.) results in the tips of the spruce tree taking on a yellow or reddish-brown appearance. It attacks only new needles on a spruce. For the life cycle of this disease to complete itself, another host plant, Labrador tea, must exist nearby. This plant is normally found in poorly drained sites, like bogs and marshes. Spruce needle rust is primarily a cosmetic problem and rarely causes serious damage to the health of the blue spruce.

Cytospora Canker

• Cytospora canker, a stem disease brought on by the fungus Leucostona kunzei is a prolific killer of several species of spruce, although it attacks the blue spruce with less frequency. It is only a serious problem in spruces that are growing outside of their native range. The first symptoms of this canker are a browning of the needles and the death of the lower branches of the tree. No fungicides exist to control cytospora canker. Removal of diseased limbs and regular fertilization of the tree minimizes the spread of the infection.

Phomopsis Occulta

• Phomopsis occulta is a fungus that causes another canker disease that regularly affects the Colorado blue spruce and several other spruce species. Infection begins with the development of lesions beneath the bark. However, other symptoms normally do not appear unless the blue spruce is stressed in another manner, such as through drought. Then, the fungus will cause needles to turn brown or purple and drop away, defoliating the tree. Application of a fungicide is vital to controlling this disease.

Rhizosphaera Needle Cast

• Rhizosphaera needle cast, caused by the fungus rhizosphaera, first displays on the lower branches of the blue spruce as second-year needles turn brown and fall away. While the fungus does not kill the tree immediately, several seasons of needle loss will eventually result in the death of the branch and a progression of the disease upward through the tree. Fungicide controls this disease if it is applied in late spring and again approximately six weeks later.