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Septoria cannabis is a species of plant pathogen from the genus Septoria that causes the disease commonly known as Septoria leaf spot. Early symptoms of infection are concentric white lesions on the vegetative leaves of cannabis plants, followed by chlorosis and necrosis of the leaf until it is ultimately overcome by disease and all living cells are then killed.
Tar spot Phyllachora cannabis: Tropical rot Lasiodiplodia theobromae = Botryodiplodia theobromae: Twig blight Dendrophoma marconii Botryosphaeria marconii [teleomorph] Verticillium wilt Verticillium albo-atrum Verticillium dahliae. White leaf spot Phomopsis ganjae: Yellow leaf spot Septoria cannabis Septoria cannabina
Puccinia thaliae is the causal agent of canna rust, a fungal disease of Canna. Symptoms include yellow to tan spots on the plant's leaves and stems. Initial disease symptoms will result in scattered sori (clustered sporangia), eventually covering the entirety of the leaf with coalescing postulates.
Infected plants display white powdery spots on the leaves and stems. [1] This mycelial layer may quickly spread to cover all of the leaves. The lower leaves are the most affected, but the mildew can appear on any above-ground part of the plant.
Leaf spots can vary in size, shape, and color depending on the age and type of the cause or pathogen. Plants, shrubs and trees are weakened by the spots on the leaves as they reduce available foliar space for photosynthesis. Other forms of leaf spot diseases include leaf rust, downy mildew and blights. [4]
Spots may fade to gray or white as the season progresses. Signs include white clusters of hyphae, which are often present on the leaves, and in some cases can infect the cone itself. If this infection occurs, a brown, necrotic lesion may develop. When both mating types exist within a population, chleistothecia can form and are visible as small ...
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Cronartium ribicola (white pine blister rust); the primary hosts are currants, and white pines the secondary. Heterocyclic and macrocyclic Heterocyclic and macrocyclic Gymnosporangium juniperi-virginianae (cedar-apple rust); Juniperus virginiana is the primary ( telial ) host and apple , pear or hawthorn is the secondary ( aecial ) host.