Bacterial blight, caused by the Pseudomonas syringae bacteria, causes various degrees of damage, depending on the specific strain of fungus attacking the viburnum. Thank You! 2. Some susceptibility to bacterial leaf spot, stem blight and powdery mildew. Bacterial leaf spot (bacterial blight) Pseudomonas syringae pv viburni. The bacterium requires a natural opening or wound to cause infection. Articles. These develop into shrunken, brown areas about 1/8-inch in diameter. Downy mildew causes leaves to develop splotched areas which die and shrivel in spring. Save For Later Print. Aphids. Previously viburnums were included in the plant family Caprifoliaceae; however, recently they have been moved into the family Adoxaceae, along with elderberries (Sambucusspecies). Bacterial Blight. Other hosts such as camellia may be infected but have only subtle symptoms, such as small leaf lesions on the lower leaves. Leaf spot: Viburnum: Disease: Various fungi cause leaf spot symptoms on viburnum. Photo: Rosetta . In more severe infections, Viburnum can be killed. Avoiding this practice will help reduce the amount of material that has the ability to become diseased. Viburnum Diseases; Viburnum Diseases. Family Caprifoliaceae, University of California IPM Online: Bacterial blight—Pseudomonas Syringae, Washington State University Extension: Viburnum: Bacterial Blight (Leaf Spot), Iowa State University Extension: Viburnum, Bacterial Leaf Spot/Leaf Blight, North Carolina State University Cooperative Extension: Viburnum Tinus. A bacterial infection can cause small water-soaked lesions on leaves and stems, and can resemble a P. ramorum infection. Grow Viburnum tinus plants in U.S. Department of Agriculture plant hardiness zones 7b to 10 for the most successful growth. Damask holds a Master of Arts in English and creative writing from the University of North Texas. Bacterial Blight causes brown leaf spots (often surrounded by yellow areas) and rapid browning of young shoots. For severe infections, provide chemical control. Â© Copyright 2020 Hearst Communications, Inc. The insects can be dislodged with high pressure water spray from the garden hose. syringae may also occur on viburnum in the PNW. Garden Uses. Bacterial leaf spot is a disease present in cool, wet weather. Although the bacteria survive on the outside of the plant they must get inside and multiply in the space between plant cells (apoplast) to cause disease. Light infestations of scale bugs can be scraped off by hand, and heavier ones can be treated with insecticide.. Other insects affecting viburnums include: Weevils – Weevils chew on the edges of leaves. When you notice blight symptoms on your viburnum, your plant is infected with a bacterial disease. Bean aphid; Armored scales. Several fungi cause leaf spots including the fungi Cercospora spp., Phoma spp. Often the new blackened tips curl over, forming a “shepherd’s crook.” … Bacterial blight is favored by cool, moist conditions. Bacterial crown gall forms galls on the lower stems. As the disease progresses, leaves may become distorted due to heavy infection. Tarah Damask's writing career began in 2003 and includes experience as a fashion writer/editor for Neiman Marcus, short fiction publications in "North Texas Review," a self-published novel, band biographies, charter school curriculum and articles for various websites. This article originally appeared in the 8/22/2003 issue. Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. Bacterial wilt occurs mainly in hot weather and heavy rains. syringae. Informational table showing disease name, symptoms, pathogen/cause, and management of Viburnum diseases. Diseases. viburni, on Viburnum can be found at the Online Guide to Plant Disease: Viburnum bacterial blight . Whether you grow Viburnum tinus -- commonly called Laurustinus -- in your garden for its white flowers, blue-black berries or interesting evergreen foliage, recognizing a blight problem means your lovely plant is in danger of losing its health. Save your viburnum from severe damage and health decline by implementing control methods as soon as symptoms appear. Young shoots and leaves are very susceptible to infection. Remove and destroy affected plant parts to decrease infection. Diseases Bacterial leafspot causes round, water-soaked spots on leaves and young stems. Invertebrates. Bacterial leaf spot is a disease of Viburnum, caused by the bacterium Pseudomonas syringae. In addition, to guard against leaf spot, avoid watering the plants from above to keep leaves as dry as possible. Disease Symptoms Pathogen/Cause Management; Botryosphaeria canker: Leaves on affected branches wilt and die. The Garden wouldn't be … (800) 262-3804, Iowa State University | PoliciesState & National Extension Partners, by Barbara Ambruzs, Department of Plant Pathology, Like us at Plant and Insect Diagnostic Clinic, Like us at Department of Plant Pathology and Microbiology, Minor leaf spots and blights of turfgrasses, Minor leaf spot diseases of maple: tar spot and leaf blister. Pests and disorders of Viburnum spp. Spots on leaves first appear as brown, watersoaked areas which may be round, irregular, or angular in outline. Anthracnose is caused by various fungi and appears as black, sunken lesions is fairly common on viburnum foliage. If this article is to be used in any other manner, permission from the author is required. Since the disease is preventable and treatable, your viburnum should not die as a result of bacterial blight. The plants affected includeAmelanchier (serviceberry), Chaenomeles (flowering quince), Cotoneaster (cotoneaster),Crataegus (hawthorn),Eriobotrya (loquat), Malus (apple and crabapple), Photinia (photinia), Prunus (flowering almond, plum and cherry), Pyracantha (pyracantha), Pyrus (pear),Rosa (rose), and Spirea(spirea). The disease initially causes sunken water-soaked leaf spots. It is most common when the weather is wet. The disease affects plants in the Rosaceae family, which includes trees and shrubs in orchards, nurseries and landscape plantings. If your Viburnum has angular shaped, water soaked, diseased areas on its leaves, the plant may have bacterial leaf spot, also known as bacterial blight. It causes angular leaf spots that appear water-soaked. This adaptable tree should be `rediscovered' by landscape architects and others specifying small trees for urban and suburban landscapes. Shrub borders or foundations. Southern red mite ; Thrips. Inspect the stems of unhealthy-looking plants for possible scale infestations. Make clean cuts when pruning; avoid pruning during wet weather. Leaf spots are first yellow then brown; Spots may be angular or have feathery edges depending on species of viburnum; Fuzzy, grayish-white areas of fungal growth may be visible on underside of blotches ; Spots may join together to form large blotches.