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Plant disease triangle. Epidemiology is the study of factors affecting the outbreak and spread of infectious diseases. [11] A disease triangle describes the basic factors required for plant diseases. These are the host plant, the pathogen, and the environment. Any one of these can be modified to control a disease. [12]
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 ]
Physiological plant disorders are caused by non-pathological conditions such as poor light, adverse weather, water-logging, phytotoxic compounds or a lack of nutrients, and affect the functioning of the plant system. Physiological disorders are distinguished from plant diseases caused by pathogens, such as a virus or fungus. [1]
Such diseases were originally thought to be caused by viruses, which, like phytoplasmas, require insect vectors and cannot be cultured. Viral and phytoplasmic infections share some symptoms. [ 5 ] In 1967, phytoplasmas were discovered in ultrathin sections of plant phloem tissue and were termed mycoplasma-like organisms due to their ...
Although the pathogens and their mechanics differ greatly from those of animals, plants are subject to a wide variety of diseases, including those caused by fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Damage caused by insects, mites, vertebrate, and other small ...
In order for heteroplasmy to occur, organelles must contain a genome and, in turn, a genotype. In animals, mitochondria are the only organelles that contain their own genomes, so these organisms will only have mitochondrial heteroplasmy. In contrast, photosynthetic plants contain mitochondria and chloroplasts, each of which contains plastid ...
Much like diseases of humans and other animals, plant diseases occur due to pathogens such as bacteria, viruses, fungi, oomycetes, nematodes, phytoplasmas, protozoa, and parasitic plants. [1] Plant disease epidemiologists strive for an understanding of the cause and effects of disease and develop strategies to intervene in situations where crop ...
Citrus blight, caused by an unknown agent, infects all citrus scions. Fire blight of pome fruits, caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., is the most severe disease of pear and also is found in apple and raspberry, among others. Bacterial leaf blight of rice, caused by the bacterium Xanthomonas oryzae (Uyeda ...