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In epidemiology, force of infection (denoted ) is the rate at which susceptible individuals acquire an infectious disease. [1] Because it takes account of susceptibility it can be used to compare the rate of transmission between different groups of the population for the same infectious disease, or even between different infectious diseases.
Plants are constantly exposed to different stresses that result in wounding. Plants have adapted to defend themselves against wounding events, like herbivore attacks or environmental stresses. [1] There are many defense mechanisms that plants rely on to help fight off pathogens and subsequent infections.
Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). [1] Organisms that cause infectious disease include fungi , oomycetes , bacteria , viruses , viroids , virus -like organisms, phytoplasmas , protozoa , nematodes and parasitic plants . [ 2 ]
Plants can show many signs or physical evidence of fungal, viral or bacterial infections. This can range from rusts or molds to not showing anything at all when a pathogen invades the plant (occurs in some viral diseases in plants). [9] Symptoms which are visible effects of diseases on the plant consist of changes in color, shape or function. [9]
Plant disease resistance is the ability of a plant to prevent and terminate infections from plant pathogens. Structures that help plants prevent pathogens from entering are the cuticular layer, cell walls, and stomata guard cells.
Plant disease resistance is crucial to the reliable production of food, and it provides significant reductions in agricultural use of land, water, fuel, and other inputs. Plants in both natural and cultivated populations carry inherent disease resistance, but this has not always protected them.
Phyllody on a purple coneflower (Echinacea purpurea). Phyllody is the abnormal development of floral parts into leafy structures. It is generally caused by phytoplasma or virus infections, [1] though it may also be because of environmental factors that result in an imbalance in plant hormones. [2]
The bacteria need a film of water to facilitate infection. The bacteria can also be transmitted from one plant to another when beetles feed on an infected plant and the bacteria becomes attached to the beetles mouthparts. [4] The bacteria Ralstonia solanacearum and related species cause bacterial wilt of bananas and plantains. [5]