Diseases+and+Treatments

=Rose Diseases and Treatments =

· **Healthy roses resist disease better. ** · **There are 3 main rose diseases: All fungal or humidity related. ** o **Black spot ** o **Powdery mildew ** o **Rust ** · **Black Spot: ** o **Random black spots on foliage. ** o **If untreated results in defoliation and loss of vigour. ** o **Thrives in high humidity, warmth and greater in coastal areas. ** o **Prevention: In high humidity climates, commence spraying in early spring with a good rose fungicide. ** o **Spray every two weeks during the season. ** o **Remove and burn infected leaves. ** · **Powdery Mildew: ** o **Occurs in fine, mild weather with overnight dew. ** o **Appears as powdery bloom on young shoots and leaves. ** o **<span style="font-family: 'Times New Roman','serif';">Causes leaves to drop prematurely. ** o **<span style="font-family: 'Times New Roman','serif';">Treatment: Spray with fungicide. ** o **<span style="font-family: 'Times New Roman','serif';">Some sprays treat mildew and black spot, e.g. //Triflorine// and //Myclobutanil//. ** · **<span style="font-family: 'Times New Roman','serif';">Rust: ** o **<span style="font-family: 'Times New Roman','serif';">Less common. ** o **<span style="font-family: 'Times New Roman','serif';">Appears as small rusty looking specks on the back of leaves with corresponding light green spots on top. ** o **<span style="font-family: 'Times New Roman','serif';">Quickly results in defoliation. ** o **<span style="font-family: 'Times New Roman','serif';">Can carry over from year to year. ** o **<span style="font-family: 'Times New Roman','serif';">Act quickly when seen. ** · **<span style="font-family: 'Times New Roman','serif';">Prevention: ** o **<span style="font-family: 'Times New Roman','serif';">Rose fertilisers higher in phosphorus and potassium increase fungal resistance. ** o **<span style="font-family: 'Times New Roman','serif';">Alternate two different fungicides to prevent fungus becoming resistant. ** · **<span style="font-family: 'Times New Roman','serif';">Viruses: Rose Wilt and Rose Mosaic ** o **<span style="font-family: 'Times New Roman','serif';">Symptoms appear in spring on new growth. ** o **<span style="font-family: 'Times New Roman','serif';">Shoots grow normally then quickly droop and look wilted, becoming brittle and fall off easily. ** o **<span style="font-family: 'Times New Roman','serif';">Whole shoot defoliates, stem dies and turns black. Stem then turns yellow, then blotchy black and dies. ** o **<span style="font-family: 'Times New Roman','serif';">Process takes 1 – 2 weeks. ** o **<span style="font-family: 'Times New Roman','serif';">Dig up and burn affected plants. ** o **<span style="font-family: 'Times New Roman','serif';">Not common, but a quick response when identified is important. **

· **<span style="font-family: 'Times New Roman','serif';">References: ** · **<span style="font-family: 'Times New Roman','serif';">MANN, R. //Roses, A Practical Guide to Over 300 Roses for Australia and New Zealand//, 2002, Harper Collins, Australia. ** · **<span style="font-family: 'Times New Roman','serif';">RUSTON, D and YOUNG, J. //The Joy of Roses//, 2004, 4c Publishers, Australia. ** · **<span style="font-family: 'Times New Roman','serif';">KERRUISH, R. M and UNGER, P. W. //Plant Protection 1. Pests, Diseases and Weeds//, 3rd Edition, 2003, Rootrot Press, Australia. **

For a printable word document click below save and print
 * Researched by:** Simon Stevens