Tiêu đề Pathology Part-1.pdf ✅

www.iaritoppers.in Whatsapp : +91-9694095242 Page | 1 Plant Pathology 5 th Edition 2024
www.iaritoppers.in Whatsapp : +91-9694095242 Page | 2 Plant disease Symptoms and Signs:  Anthracnose: Ulcer -like lesions on stem and pods.  Blight: sudden death of twigs, foliage, and/or flowers. Burnt like appearance.  Blotch: large and irregular-shaped spots or blots on leaves, shoots, and stems.  Canker: dead places on bark and cortex of twigs or stems; often discolored and raised or sunken.  Chlorosis: yellowing of normally green tissue due to reduced chlorophyll content, such tissue is chlorotic.  Conks: fungal fruiting structures formed on rotting woody plants (shelf or bracket fungi).  Damping-off: destruction of seeds in the soil, or seedlings near the soil line, resulting in reduced stand, or the seedling falling over on the ground  Decline: progressive, gradual weakening and death of a plant or population of plants  Dieback: progressive, gradual weakening and death of individual branches of a plant, often leading to decline  Distortion: malformed plant tissues  Etiolation: When the loss of green colour is due to prolonged exposure to darkness the condition is called etiolation.  Exudation: Masses of bacterial cell ooze out to the surface of affected plant parts and form some drops or smear, it is called exudation.  Eradication: Complete removal of plant diseases (reduction to xero)  Flagging: the loss of rigidity and drooping of leaves and tender shoots preceding the wilting of a plant.  Fleck: a minute spot  Galls: abnormal, localized swellings or tumors, on leaf, stem or root tissue  Gum: complex of sugary substances formed by cells in reaction to wounding or infection  Gummosis: production of gum by or in a plant tissue.  Hyperplasia: It is the abnormal increase in size of the organ due to an increase in number of cells of organ (due to cell division).  Hypertrophy: Increased size of organ is due to increase in size of cells (owing to nucleus division).  Inoculum: amount of pathogen available for infection  Leaf spot: a self-limiting lesion on a leaf  Lesion: a localized area of discolored, diseased tissue  Malignant: tissue that divides and enlarges autonomously, forming a tumor or gall  Masked symptoms: virus-induced plant symptoms that are normally, but appear when the host is exposed to certain environmental conditions of light and temperature
www.iaritoppers.in Whatsapp : +91-9694095242 Page | 3  Mildew: a plant disease in which the pathogen is seen as a growth on the surface of the host; e.g., downy mildew, powdery mildew, caused by very different fungi, but both having the name Mildew.  Downy Mildew: The superficial growth of the pathogen is a cottony or downy layer of leaves surface. Downey mildew fungal genus plasmopara have obtuse sporangia and secondary and tertiary branches emerge at right angle. (AFO-2024)  Powdery Mildew: Dusty or powdery appearance (growth) of fungus on upper surface of plants.  Mosaic: symptom of certain viral diseases of plants characterized by intermingling patches of normal green and light green or yellowish colors  Mottle: an irregular pattern of indistinct light and dark green areas  Mummy: a dried shriveled fruit  Mycelium: masses of fungal threads (hyphae) which compose the vegetative body of the fungus  Necrosis: death of tissue  Necrotic: dead or discolored brown to black  Ooze: a mass of bacterial cells usually embedded in a slimy matrix appearing on the diseased plant surface, often as a droplet; or, a flux, a viscid mass of juices composed of host and parasite substances occasionally found exuding from a diseased plant  Pycnidia: minute, usually globose and black, fungal asexual fruiting structures formed on plant surfaces  Phyllody: It is a serious problem of sesame and pearl millet. Transformation of floral part in green leafy structure.  Rhizomorphs: string-like strands of fungal mycelia sometimes found under bark of trees  Ring spot: a circular area of chlorosis with a green center; a symptom of many virus diseases  Rot: the softening, discoloration, and disintegration of succulent plant tissue as the result of fungal or bacterial infection  Russet: brownish roughened areas on skin of fruit as a result of cork formation  Rust: a type of disease caused by a specific group of fungi, often producing orange-red "rust" colored spores.  Smut: Sooty or charcoal -like powder. Plant shows a black or purplish black dusty mass composed of the fungus spores particularly in ovulary part of floral organs.  Scab: a roughened crust-like diseased area on the surface of a plant organ; a disease in which such areas form  Sclerotia: tough structures produced by fungi for long-term survival.  Scorch: burning of leaf margins as a result of infection or unfavorable environmental conditions  Shot-hole: a symptom in which small diseased fragments of leaves fall off and leave small holes in their place
www.iaritoppers.in Whatsapp : +91-9694095242 Page | 4  Signs: visible evidence of the pathogen; signs are not the same as symptoms  Spots: circular or irregular lesions on above ground tissue  Tip blight: death of shoot tips  Tumor: a malignant overgrowth of tissue  Vein banding: retention of bands of green tissue along the veins while the tissue between veins has become chlorotic. Example: Potato vein banding disease by Potato vein banding virus.  Vein clearing: destruction of chlorophyll adjacent or in the vein tissue as a result of infection by a virus or other pathogen. Yellow network of veins is the major characteristics of vein clearing in okra.  Wilt: loss of rigidity and drooping of plant parts generally caused by insufficient water in the plant.  Witches' broom: broom-like growth or massed proliferation caused by the dense clustering of branches in woody plants.  Yellows: a group of systemic mycooplasma-caused diseases often resulting in wilt, witches broom, or decline.  Alternate host: is the host that help in the completion of the life cycle of the pathogen and its survival, belong to diff. family.  Collateral host: host of the same family and help in the survival of the pathogen.  Infection: Establishment of organic relationship between host and pathogen.  Pathogenesis: Chain of events that takes place during the development of disease (inoculation to survival of the pathogen).  Susceptibility: Inability of the host to resist the attack of the pathogen.  Virulence: It is defined as the degree of pathogenecity of a particular isolate or race of the pathogen.  Parasite: An organism that lives on or in another organism and obtains food from the second organism.  Pathogen: Any entity that can cause disease in a host eg. Fungus, Bacteria, virus, Phytoplasma, Viroids, RLO’s, Parasitic Plants, Nematodes. Common Remedy for some diseases:  Powdery mildew: Sulphur fungicide  Downy Mildew: Metalaxyl  Rust: Plantavax  Smut: Vitavax