Fungus on Jasmine

Sooty Mold

• Sooty mold does not directly injure jasmine plants but it does indicate a pest problem and affects the appearance of the jasmine. Certain potential pests of jasmine -- including mealybugs, scales and whiteflies -- produce, as a byproduct of feeding, a sugary, shiny-looking substance known as honeydew. This honeydew attracts ants and also hosts the growth of unsightly sooty mold. The mold only injures the jasmine if it covers enough leaf surface to interfere with photosynthesis. Addressing the pests responsible for the honeydew is necessary to prevent further sooty mold growth, while weathering or repeated washing will eventually wear off the mold already present.

Gray Mold

• Gray mold, also known as Botrytis blight or Botrytis mold, is caused by the fungal pathogen Botrytis cinerea. This disease usually first appears as small, reddish or brown dots on jasmine flowers before the infected areas are covered with indicative gray, fuzzy growth. In severe cases, portions of the jasmine may die back. Botrytis, which prefers rainy, humid conditions, is addressed by pruning out and disposing of infected portions of the jasmine when conditions are dry.

Leaf Spots and Rusts

• Various species of fungi including Phyllosticta, Cercospora and Alternaria can cause leaf spots or rusts on jasmine, generally appearing as brown or otherwise dark spots that are sometimes surrounded by yellowing tissue. Fungal spores generally spread and infect jasmine during wet, rainy weather. Rust appears as blisters of rust-colored spores on leaves that turn yellow and may experience distortion. To avoid problems with fungal leaf spots, prune out jasmine stems selectively to ensure excellent air circulation around the plants and avoid sprinkler irrigation or other splashing water. Where jasmine is infected, good sanitation is crucial. Prune out infected portions of the jasmine when conditions are dry, and destroy or dispose of them away from desirable vegetation. Also rake up fallen debris regularly. On particularly prized jasmines or where fungal leaf spots were problematic in previous years, preventative copper fungicide sprays may be warranted.

Wilt and Root Rot

• Fusarium wilt, caused by a fungus of the same name, and Southern blight, caused by Sclerotium rolfsii, cause a yellowing of foliage beginning near the bottom of the plant and progressing upwards followed by eventual plant death. Southern blight, sometimes also known as sclerotial wilt, is usually identified by white, threadlike growth fanning up the jasmine's stem and out into the soil. Pythium root rot can also affect jasmine. Planting jasmine in a site where plants have not previously suffered from root rots or wilts, making sure that the soil offers excellent drainage and avoiding overwatering will limit the potential for these diseases.

Powdery Mildew

• Powdery mildew appears on jasmine as patches or spots of white or grayish, powdery growth that first develops on the upper surface of leaves before progressing to leaf undersides, buds and flowers. Leaves turn yellow and drop prematurely. Pruning jasmine stems selectively to thin plants out and improve air circulation and avoiding excessive nitrogen fertilizer applications will help to prevent the presence of this disease. Where powdery mildew is present, carefully prune out and destroy infected portions and, if necessary, spray infected plants with horticultural oil.