One such issue, powderymildew on asters, causes damage to the plant and rendering it unsightly. Learn how to treat it in this article. Asters are particularly susceptible to this common fungal disease. A wide number of garden plants develop this disease to the extent that it is possible to buy plants that are mildew resistant.With a bit of luck you will be able to control the spread of powderymildew in your garden. Asters have a tendency to suffer from powderymildew, which is a fungal disease that shows up as a powdery coating on the foliage. For prevention, plant your plants widely to allow for air circulation. Also trim your aster stems and rake around your asters to increase air circulation and remove organic matter that powderymildew is prone to attack. Botrytis cinerea and root rot are common in water-stressed asters. Both are fungal diseases that cause sporangia to form on parts. Aster-PowderyMildew. Facebook logo. Latest revision: March 2025.Symptoms Powdery white or gray-white fungus growth on leaves and stems of aster. On some plants, a purplish discoloration and leaf distortion may occur. Cultural control. Powderymildew is one of the most common diseases to impact plants. While almost no type of plant is immune, certain species are more susceptible than others. Luckily, there are effective powderymildew treatments that can help fight the disease. Growing Aster – Michaelmas Daisies. The asters which we grow are clump forming rhizomatous perennials with slender branched stems and stalk less lance shaped leaves. The flowers brighten up most herbaceous borders from late summer and on into autumn. Advice on buying asters. Choose your aster flowers carefully – if you have drier soils then opt for European or certified mildew-resistant varieties. Always check plants for signs of damage or disease before buying or planting. How to Prevent and ControlPowderyMildew. powderymildew plant disease on a yellow summer squash plant and leaves. Aromatic aster outperformed the familiar, often-recommended species, New England aster (Symphotrichum novae-angliae). The New England aster was more susceptible to powderymildew than was aromatic aster, and its habit was leggier. Powderymildew fungi produce microscopic air-borne dispersal spores with an unusually high water content, enabling them to infect underdrier conditions. Some asters, surprisingly, are unaffected by mildew, the elegant, willowy six-footer, Climax, with panicles of powder-blueflower... PowderyMildew – Aster ‘Cassandra’ was selected as a known disease susceptible cultivar for use following discussion with Lyndon Mason, Cut Flower Centre. The Aster crop was infected at the beginning of the trial following the introduction of infector plants. Powderymildew can be prevented by maintaining optimum plant health and not overcrowding at planting. For information on controllingpowderymildew, see fact sheet HGIC 2049, PowderyMildew. Aster Yellows is transmitted to the plant as leafhoppers feed on the plant. Notable among these diseases are root, crown, and stem rots; powderymildew; black leaf spot; aster yellows; and several viral diseases. Yield loss can be reduced and profitability increased by concerted efforts to manage delphinium diseases.
