Instruct: Given a question, retrieve relevant passages that answer the question.
Query: How do plants get blight?
To continue, the symptoms of this bacterial blight include spots and lesions on leaves, and rot of floral buds and flowers. The floral symptoms undergo changes throughout the seasons that ultimately end in the floral bud dying and falling off. These symptoms are found initially as brown and sunken spots on the green sepals of the vine that enclose the flower buds. The result is the flower buds begin to rot when unopened. If the buds do open and yield a yellow-orange color, rather than white, the flower turns brown rather quickly and dies. In addition, the anthers or male sexual parts of the flower can be destroyed in this disease causing an incomplete retraction of sepals. Regarding the leaves, symptoms are visible in later spring and are found on the lower leaves first. The lesions created are angular and gray on the lower leaves, and the lesions are surrounded with a yellow halo on the upper leaves. These lesions turn brown and can be a site for a secondary infection by a fungus or some other pathogen. All of this leads to abnormal fruit development on diseased plants which can create an economic problem for the grower. Fruit development is the largest economical concern when referring to this pathogen. Yield loss can become very high, reaching over 90% in orchards that have symptoms of this pathogen. When no symptoms are present, however, the plant is healthy and fruit development is normal. It is stated that it is very rare to find normal fruit development on plants with symptoms of bacterial blight showing how detrimental this disease and pathogen is.
Striga hermonthica, commonly known as purple witchweed or giant witchweed, is a hemiparasitic plant that belongs to the family Orobanchaceae. It is devastating to major crops such as sorghum ("Sorghum bicolor") and rice ("Oryza sativa"). In sub-Saharan Africa, apart from sorghum and rice, it also infests maize ("Zea mays"), pearl millet ("Pennisetum glaucum"), and sugar cane ("Saccharum officinarum").
BABA was first found to increase the resistance of plants to disease in 1960, when it was observed that it decreased late blight of tomato. Further tests were made in the 1960s, but it was not until the 1990s that interest in the compound was renewed. Since then, it has been shown to be effective in many different pathosystems under controlled conditions. Both perennial and annual plants have been shown to respond, as well as both monocot and dicot plants in the Solanaceae, Cucurbitaceae, Compositae, Fabaceae, Brassicaceae, Graminae, Malvaceae, Rosaceae, and Vitaceae families. Pathogen groups that have shown a response include viruses, bacteria, nematodes, fungi and oomycetes. It has also been shown to be effective in the field at protecting potato and tomato plants from late blight, grape vines from "Plasmopara viticola" and melons from "Monosporascus cannonballus".
Various forms of mildew and blight are common tomato afflictions, which is why tomato cultivars are often marked with a combination of letters that refer to specific disease resistance. The most common letters are: LB – "late blight", V – "verticillium" wilt, F – "fusarium" wilt strain I, FF – "fusarium" wilt strain I and II, N – "nematodes", T – "tobacco mosaic virus", and A – "alternaria".
Wheat diseases such as wheat bunt and stinking smut can be successfully treated with a fungicide. 
Disease of plants and animals can break an agricultural producer. Tuberculosis in animals was an early threat, and cattle needed to be tested, and areas accredited in 1956. The newer disease such as chronic wasting disease or transmissible spongiform encephalopathy (TSE) affects both elk and deer. Elk and deer raising is a pioneer field of domestication, has had a setback with this disease. Mad cow disease in cattle and scrapie of sheep are monitored by the Canadian Food Inspection Agency. The poultry sector was plagued by Pullorum disease, and by controlling the flock via poultry husbandry, this disease has been brought under control.
Soybean is one of the most important commercial crops around the world and in the United States. Asian soybean rust is the major disease that affects soybeans. It causes lesions on the leaves of soybean plants and eventually kills the plants. The disease has caused serious yield loss of soybeans. In the areas where this disease is common, the yield losses can be up to 80%. In 2002, USDA reported 10-60% of yield losses in South America and Africa.
Common plants used to remediate indoor air pollutants include: English ivy ("Hedera helix"), Peace lily ("Spathiphyllum ‘Mauna Loa’"), Chinese evergreen ("Aglaonema modestum"), Bamboo palm ("Chamaedorea seifrizii"), and Chrysanthemum ("Chrysanthemum morifolium"). There are several studies that cite the plant microcosm as a mechanism to reduce indoor VOCs. Controls of just pots alone and just a tray of water suggest that it is the soil microcosm that provides the pollutant sink. The role of the plants is to establish and maintain the species specific root-zone microbial communities. This mechanism was first suggested by Wolverton et al. in 1985. Houseplants also aid in humidity, temperature, and noise control.
The "Clostridium botulinum" bacteria are the cause of botulism. Vegetative cells of "C. botulinum" may be ingested. Introduction of the bacteria may also occur via endospores in a wound. When the bacteria are in vivo, they induce flaccid paralysis. This happens because "C. botulinum" produces a toxin which blocks the release of acetylcholine. Botulism toxin blocks the exocytosis of presynaptic vesicles containing acetylcholine (ACh). When this occurs, the muscles are unable to contract. Other symptoms associated with infection from this neurotoxin include double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness. Botulism prevents muscle contraction by blocking the release of acetylcholine, thereby halting postsynaptic activity of the neuromuscular junction. If its effects reach the respiratory muscles, then it can cause respiratory failure, leading to death.
Research and development in managing "P. ramorum" in nursery settings extends from "P. ramorum" in the individual plant, to "P. ramorum" in the nursery environment, to the pathogen’s movement across state and national borders in infected plants.
Plants can absorb nitrate or ammonium from the soil via their root hairs. If nitrate is absorbed, it is first reduced to nitrite ions and then ammonium ions for incorporation into amino acids, nucleic acids, and chlorophyll. In plants that have a symbiotic relationship with rhizobia, some nitrogen is assimilated in the form of ammonium ions directly from the nodules. It is now known that there is a more complex cycling of amino acids between "Rhizobia" bacteroids and plants. The plant provides amino acids to the bacteroids so ammonia assimilation is not required and the bacteroids pass amino acids (with the newly fixed nitrogen) back to the plant, thus forming an interdependent relationship. While many animals, fungi, and other heterotrophic organisms obtain nitrogen by ingestion of amino acids, nucleotides, and other small organic molecules, other heterotrophs (including many bacteria) are able to utilize inorganic compounds, such as ammonium as sole N sources. Utilization of various N sources is carefully regulated in all organisms.
In the Scottish Highlands, in 1846, there was widespread failure of potato crops as a result of potato blight. Crops failed in about three-quarters of the crofting region, putting a population of about 200,000 at risk; the following winter was especially cold and snowy and the death rate rose significantly. The Free Church of Scotland, strong in the affected areas, was prompt in raising the alarm and in organising relief, being the only body actively doing so in late 1846 and early 1847; relief was given regardless of denomination. Additionally, the Free Church organised transport for over 3,000 men from the famine-struck regions to work on the Lowland railways. This both removed people who needed to be fed from the area and provided money for their families to buy food.
Early detection of "P. ramorum" is essential for its control. On an individual-tree basis, preventive treatments, which are more effective than therapeutic treatments, depend on knowledge of the pathogen’s movement through the landscape to know when it is nearing prized trees. On the landscape level, "P. ramorum’s" fast and often undetectable movement means that any treatment hoping to slow its spread must happen very early in the development of an infestation. Since "P. ramorum’s" discovery, researchers have been working on the development of early detection methods on scales ranging from diagnosis in individual infected plants to landscape-level detection efforts involving large numbers of people.
Food-borne botulism results, indirectly, from ingestion of food contaminated with Clostridium spores, where exposure to an anaerobic environment allows the spores to germinate, after which the bacteria can multiply and produce toxin. Critically, "it is ingestion of toxin rather than spores or vegetative bacteria" that causes botulism. Botulism is nevertheless known to be transmitted through canned foods not cooked correctly before canning or after can opening, and so is preventable. Infant botulism cases arise chiefly as a result of environmental exposure and are therefore more difficult to prevent. Infant botulism arising from consumption of honey can be prevented by eliminating honey from diets of children less than 12 months old.
A few strains from organisms genetically identified as other "Clostridium" species have caused human botulism: "C. butyricum" has produced type E toxin and "C. baratii" had produced type F toxin. The ability of "C. botulinum" to naturally transfer neurotoxin genes to other clostridia is concerning, especially in the food industry, where preservation systems are designed to destroy or inhibit only "C. botulinum" but not other "Clostridium" species.
Botulism is a rare and potentially fatal illness caused by a toxin produced by the bacterium "Clostridium botulinum". The disease begins with weakness, blurred vision, feeling tired, and trouble speaking. This may then be followed by weakness of the arms, chest muscles, and legs. Vomiting, swelling of the abdomen, and diarrhea may also occur. The disease does not usually affect consciousness or cause a fever.
Botulism can be spread in several ways. The bacterial spores which cause it are common in both soil and water. They produce the botulinum toxin when exposed to low oxygen levels and certain temperatures. Foodborne botulism happens when food containing the toxin is eaten. Infant botulism happens when the bacteria develops in the intestines and releases the toxin. This typically only occurs in children less than six months old, as protective mechanisms develop after that time. Wound botulism is found most often among those who inject street drugs. In this situation, spores enter a wound, and in the absence of oxygen, release the toxin. It is not passed directly between people. The diagnosis is confirmed by finding the toxin or bacteria in the person in question.
Prevention is primarily by proper food preparation. The toxin, though not the organism, is destroyed by heating it to more than for longer than 5 minutes. Honey can contain the organism, and for this reason, honey should not be fed to children under 12 months. Treatment is with an antitoxin. In those who lose their ability to breathe on their own, mechanical ventilation may be necessary for months. Antibiotics may be used for wound botulism. Death occurs in 5 to 10% of people. Botulism also affects many other animals. The word is from Latin, "botulus", meaning sausage. Early descriptions of botulism date from at least as far back as 1793 in Germany.
Botulinum toxin produced by "Clostridium botulinum" is the cause of botulism. Humans most commonly ingest the toxin from eating improperly-canned foods in which "C. botulinum" has grown. However, the toxin can also be introduced through an infected wound. In infants, the bacteria can sometimes grow in the intestines and produce botulinum toxin within the intestine and can cause a condition known as floppy baby syndrome. In all cases, the toxin can then spread, blocking nerves and muscle function. In severe cases, the toxin can block nerves controlling the respiratory system or heart, resulting in death.
Utricularia purpurea, the eastern purple bladderwort, is a medium-sized suspended aquatic carnivorous plant that belongs to the genus "Utricularia". "U. purpurea" is endemic to North and Central America. It has been suggested that "U. purpurea" may have partially lost its appetite for carnivory. Richards (2001) did an extensive study in the field on it and noted that trapping rates of the usual "Utricularia" prey were significantly lower than in other species in the genus. Richards concludes that this species can still trap and digest arthropod prey in its specialized bladder traps, but does so sparingly. Instead, it harbors a community of algae, zooplankton, and debris in the bladders that indicates "U. purpurea" favors a mutualistic interaction in place of a predator–prey relationship.
In all cases, illness is caused by the botulinum toxin produced by the bacterium "C. botulinum" in anaerobic conditions and not by the bacterium itself. The pattern of damage occurs because the toxin affects nerves that fire (depolarize) at a higher frequency first.
The first genetically modified crop plant was produced in 1982, an antibiotic-resistant tobacco plant. The first field trials of genetically engineered plants occurred in France and the USA in 1986, tobacco plants were engineered to be resistant to herbicides. In 1987 Plant Genetic Systems, founded by Marc Van Montagu and Jeff Schell, was the first company to genetically engineer insect-resistant plants by incorporating genes that produced insecticidal proteins from Bacillus thuringiensis (Bt) into tobacco.
Until 2005, three tiny parcels of ungrafted Pinot noir that escaped phylloxera were used to produce Bollinger Vieilles Vignes Françaises, one of the rarest and most expensive Champagnes available. In 2004, one of the parcels, Croix Rouge in Bouzy, finally succumbed to phylloxera and was replanted with grafted rootstock.
A houseplant is a plant that is grown indoors in places such as residences and offices. Houseplants are commonly grown for decorative purposes, but studies have also shown them to have positive psychological effects. Houseplants also help with indoor air purification. Some species, and the soil-dwelling microbes associated with them, reduce indoor air pollution by absorbing volatile organic compounds including benzene, formaldehyde, and trichloroethylene. While generally toxic to humans, such pollutants are absorbed by the plant and its soil-dwelling microbes without harm. Common houseplants are usually tropical or semi-tropical epiphytes, succulents or cacti.
Plant pathologists, Drs. William Powell and Charles Maynard, working at the State University of New York College of Environmental Science and Forestry, have developed American chestnuts which have full blight resistance. Full resistance was attained by introducing a wheat gene coding for the enzyme oxalate oxidase into the American chestnut genome. This enzyme breaks down the oxalic acid secreted by the fungus into carbon dioxide and hydrogen peroxide. Early studies on hypovirulence showed that less virulent strains of the chestnut blight produced less oxalic acid when attacking the cambium. The transgenic trees have blight resistance either equal to or surpassing that of Chinese chestnuts. In 2013, SUNY ESF had over 100 individual events being tested, with more than 400 slated to be in the field or in the lab for various assay tests in the next several years and more than 1,000 trees growing in several field sites in 2014. Government approval will be required before returning any of these blight resistant trees to the wild. The New York Botanical Garden has planted several of the transgenic trees for public display.
Current efforts are under way by the Forest Health Initiative to use modern breeding techniques and genetic engineering to create resistant tree strains, with contributions from SUNY College of Environmental Science and Forestry, Penn State, the University of Georgia, and the US Forest Service. One of the most successful methods of breeding is to create a back cross of a resistant species (such as one from China or Japan) and American chestnut. Researchers identified 2 or 3 genes that allow for blight resistance, and are focusing on giving the American chestnut hybrids only those genes from the Chinese or Japanese chestnut. The two species are first bred to create a 50/50 hybrid. After three back crosses with American chestnut, the remaining genome is approximate 1/16 that of the resistant tree, and 15/16 American. The strategy is to select blight-resistance genes during the back crossing, while preserving the more wild-type traits of American chestnut as the dominant phenotype. Thus, the newly bred hybrid chestnut trees should reach the same heights as the original American chestnut. Many of these 15/16 American chestnut hybrids have been planted along the East Coast, including in the Jefferson National Forest and on the Flight 93 National Memorial. Some of these sites have had researchers check on the saplings that have been planted to see their survival rate. For the hybrids to do well, they need areas with decent drainage and abundant sunlight. Meeting these needs can be hard to do, so not all restoration areas have been successful with hybrid survival.
Spraying plants with streptomycin or injecting plants with oxytetracycline can prevent new infections. The widespread use of streptomycin spray has led to antibiotic resistance in some areas, such as California and Washington. Certain biological controls consisting of beneficial bacteria or yeast can also prevent fire blight from infecting new trees. The only effective treatment for plants already infected is to prune off the affected branches and remove them from the area. Plants or trees should be inspected routinely for the appearance of new infections. The rest of the plant can be saved if the blighted wood is removed before the infection spreads to the roots. There is no known cure; prevention is the key.
Other methods include starting with disease free plants, buying cultivars that are less susceptible to raspberry spur blight such as Brandywine, Killarney, Latham and Newburgh, and avoiding cultivars that have greater susceptibility such as Royalty, Titan, Canby, Skeena, Willamette, Reveille, and Sentry. Willamette readily infects with spur blight but is tolerant to the disease and still produces satisfactory yields.