dark purple to black coloured spots on the leaf blade. As spots enlarge, the centres often turn light tan. At temperatures exceeding 30°C, distinct spots are often absent and the entire leaf blade Bipolaris sorokiniana appears dry and straw coloured. A Perennial (syn. Hot, humid warm weather disease affecting leaf Leaf spot ryegrass, Tall Helminthosporium conditions. sheaths, crowns and roots. Severe fescue sativum) thinning of turfgrass stand can occur in a short time (Vargas, 2005). Reduces yield and quality of tall fescue and its ability to recover after grazing. Longer the infection, greater the losses (Clarke and Eagling, 1994). In spring spores are produced and can be transferred to healthy plant tissue, but the Drechslera leaf-spot phase is Initially occurs as irregular dark dictyoides Paul and inconspicuous at purple to black transverse strands, Parbery (syn. this time. Crown resembling dark threads drawn Net-blotch Tall fescue Helminthosporium and root infection across the leaf creating a net-like dictyoides is thought to take appearance (Clarke and Eagling, Drechslera) place in spring, 1994). but symptoms are not expressed until the warm, dry weather of summer. Ryegrass Perennial Reductions in dry weight yields mosaic virus ryegrass (Clarke and Eagling, 1994). (RMV) elongated, 1-10 × mm pustules with ragged edges Perennial occur on the leaves, stems and ryegrass, seed head. Later in the season the Stem rust Puccinia graminis Italian pustules may turn black when the ryegrass, Tall fungus produces a resting stage fescue spore (teliospore). These spores, in Australia, have no further part in the
Leaf spot Bipolaris sorokiniana (syn. Helminthosporium sativum) Perennial ryegrass, Tall fescue Hot, humid conditions. dark purple to black coloured spots on the leaf blade. As spots enlarge, the centres often turn light tan. At temperatures exceeding 30°C, distinct spots are often absent and the entire leaf blade appears dry and straw coloured. A warm weather disease affecting leaf sheaths, crowns and roots. Severe thinning of turfgrass stand can occur in a short time (Vargas, 2005). Reduces yield and quality of tall fescue and its ability to recover after grazing. Longer the infection, greater the losses (Clarke and Eagling, 1994). Net-blotch Drechslera dictyoides Paul and Parbery (syn. Helminthosporium dictyoides Drechslera) Tall fescue In spring spores are produced and can be transferred to healthy plant tissue, but the leaf-spot phase is inconspicuous at this time. Crown and root infection is thought to take place in spring, but symptoms are not expressed until the warm, dry weather of summer. Initially occurs as irregular dark purple to black transverse strands, resembling dark threads drawn across the leaf creating a net-like appearance (Clarke and Eagling, 1994). Ryegrass mosaic virus (RMV) Perennial ryegrass Reductions in dry weight yields (Clarke and Eagling, 1994). Stem rust Puccinia graminis Perennial ryegrass, Italian ryegrass, Tall fescue elongated, 1-10 × mm pustules with ragged edges occur on the leaves, stems and seed head. Later in the season the pustules may turn black when the fungus produces a resting stage spore (teliospore). These spores, in Australia, have no further part in the
The%20Biology%20of%20Ryegrass%20and%20Tall%20fescue%202017.docx