Common Diseases
Apple Scab
Scab may occur on leaves, fruit, leaf and fruit stems, and green twigs. Infections of the leaves and fruit are most common and obvious. Early season infections usually occur on the underside of the blossom cluster leaves because these are the first tissue surfaces to emerge from buds in the spring. Once the cluster leaves have unfolded and terminal leaves begin to develop, infections become evident on the upper surface of the leaves. Individual infections appear as roughly circular, brown to dark olive-green spots (lesions), which often seem slightly fuzzy or velvety in texture. Read More
Cedar-Apple Rust
Hawthorn rust is caused by the fungus Gymnosporangium globosum. The rust fungus causes small yellow spots on hawthorn leaves. These spots eventually enlarge and often have a reddish border. Read More
Diploda Tip Blight
Tip blight is a disease that affects pines worldwide. This disease was previously known as Diplodia tip blight. Sphaeropsis blight is considered to be a "disfiguring disease" that attacks pine trees that are growing under stressful conditions. Read More
Dothistroma Needle Cast
Infections first appear as yellow and tan spots in bands extending around the needles. The bands often turn red, and the disease is sometimes called the red band disease or red-banded needle blight. Both old and new needles may be infected, but the infection periods differ. Read More
Dutch Elms Disease
A fungal disease of elm trees which is spread by the elm bark beetle. Although believed to be originally native to Asia, it has been accidentally introduced into America and Europe, where it has devastated native populations of elms which had not had the opportunity to evolve resistance to the disease. Read More
Sycamore Anthracnos
Common name given to a group of fungal pathogens which cause dark, unually sunken lesions. These are typically diseases of leaves, stems or fruits. The anthracnose attack sycamore trees early in the spring, causing a rapid wilt of newly emerging leaves. Read More
Phomopsis Tip Blight and Kabatina Tip Blight
Two common diseases of junipers found in most states east of the Mississippi. Both diseases are caused by fungi and the damage they cause on nursery stock, transplants and certain juniper varieties in the landscape can be severe; however, most established junipers in the landscape are seldom killed. The disease is most serious on younger plants and becomes less serious as plants get older. Read More
Apple Scab
Scab may occur on leaves, fruit, leaf and fruit stems, and green twigs. Infections of the leaves and fruit are most common and obvious. Early season infections usually occur on the underside of the blossom cluster leaves because these are the first tissue surfaces to emerge from buds in the spring. Once the cluster leaves have unfolded and terminal leaves begin to develop, infections become evident on the upper surface of the leaves. Individual infections appear as roughly circular, brown to dark olive-green spots (lesions), which often seem slightly fuzzy or velvety in texture. Read More
Cedar-Apple Rust
Hawthorn rust is caused by the fungus Gymnosporangium globosum. The rust fungus causes small yellow spots on hawthorn leaves. These spots eventually enlarge and often have a reddish border. Read More
Diploda Tip Blight
Tip blight is a disease that affects pines worldwide. This disease was previously known as Diplodia tip blight. Sphaeropsis blight is considered to be a "disfiguring disease" that attacks pine trees that are growing under stressful conditions. Read More
Dothistroma Needle Cast
Infections first appear as yellow and tan spots in bands extending around the needles. The bands often turn red, and the disease is sometimes called the red band disease or red-banded needle blight. Both old and new needles may be infected, but the infection periods differ. Read More
Dutch Elms Disease
A fungal disease of elm trees which is spread by the elm bark beetle. Although believed to be originally native to Asia, it has been accidentally introduced into America and Europe, where it has devastated native populations of elms which had not had the opportunity to evolve resistance to the disease. Read More
Sycamore Anthracnos
Common name given to a group of fungal pathogens which cause dark, unually sunken lesions. These are typically diseases of leaves, stems or fruits. The anthracnose attack sycamore trees early in the spring, causing a rapid wilt of newly emerging leaves. Read More
Phomopsis Tip Blight and Kabatina Tip Blight
Two common diseases of junipers found in most states east of the Mississippi. Both diseases are caused by fungi and the damage they cause on nursery stock, transplants and certain juniper varieties in the landscape can be severe; however, most established junipers in the landscape are seldom killed. The disease is most serious on younger plants and becomes less serious as plants get older. Read More