Irish Famine (1845–1849), and still remains the most destructive pathogen of solanaceous crops, including tomato and potato. The soya bean root and stem rot agent, Phytophthora sojae (Anon., 2016e).
e) Macrophomina: It has a very wide host distribution covering most of the tropics and subtropics, extending well into temperate zones (Songa 1995).
f) Fusarium: The fungal pathogen Fusarium oxysporum cause disease to a wide variety of hosts of any age. Tomato, tobacco, legumes, cucurbits, sweet potatoes and banana are a few of the most susceptible plants to this pathogen.
g) Verticillium: Many economically important plants are susceptible including cotton, tomato, potato, brinjal, pepper and ornamentals.
4.2. Bacteria :
Pseudomonas:
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Colonization of a root occurs at fine scales with growth and movement of fungal mycelia through soil. However, epidemics are observed at coarser scales and depend on a cascading spread through populations of roots.
5.1. Factors influencing the soil borne plant pathogens :
a) Moisture: Moisture is of utmost importance for pathogenic fungi and bacteria. Rain splash plays an important role in the dispersal of some fungi and nearly all bacteria, and a period of leaf wetness is necessary for the germination of spores. Propagules germinate in the presence of water and are dispersed. Because the process of germination and infection takes time, the duration of leaf wetness also affects the occurrence of the infection. The duration necessary for infection varies with temperature. Usually, a longer period of leaf wetness is needed to establish an infection in cooler temperatures, as germination and infection are generally accelerated in warmer conditions.
b) Temperature: Temperature affects the incubation or latent period (the time between infection and the appearance of disease symptoms), the generation time (the time between infection and sporulation), and the infectious period (the time during which the pathogen keeps producing propagules). The period of leaf wetness and temperature information is being used to predict outbreaks of diseases (infection periods) and can be helpful in prophylactic
The pathogens that infect humans grow best at body temperature of 37*C. Higher temperatures inactivate and kill most of the micro-organisms, while low temperatures slow or stop their grow. That is why heat is used to steralize objects, while freezing is used to preserve food.
This experiment is designed to test the allelopathy of two different treatments, Eucalyptus (Eucalyptus cinerea) and Lemon (Citrus limon). The two treatments will be tested on radish seeds (Raphanus sativus) to investigate the effect of the treatments on the germination of the radish seeds. Allelopathy is the beneficial or harmful effects that one plant has on another plant by the release of chemicals. Allelopathy studies the interactions among plants, fungi, algae and bacteria with the organisms living in a certain ecosystem, interactions that are mediated by the secondary metabolites produced and exuded into the environment (Francisco A Macías, José MG Molinillo, Rosa M Varela, Juan CG Galindo 2007). The plants use
Yaqoob Thurston is an PH.D. candidate in the Plant Science Department at South Dakota State University. His work combines molecular biology, molecular genetics of pathological, symbiotic and associative interactions, molecular plant breeding, and microbiology as a major platform used to understand the nature and consequences of plant microbial interactions. Specially, Mr. Thurston methodological research concentrates on the interaction of fungal pathogens fusarium head blight (FHB), and the symbiotic interaction arbuscular mycorrhizae fungi (AMF) with wheat.
Cryphonectria parasitica, a filamentous, ascomycete fungus, is the causal agent of the chestnut blight5,14 which was introduced to North America from Japan circa 190412,14.The chestnut blight infects all members of the Castanea family14, and some members of the genus Quercus though C. parasitica infections are superficial14. A C. parasitica infection typically begins at a branch node or wound in the tree’s bark 14. Once a spore has entered the tree, hyphal growth begins14. When the fungi’s hyphae reach the cambium, the xylem and phloem are blocked, cutting off the transport of water and nutrients and a sunken canker is formed14. Eventually, the lack of water and nutrients kills the tree above the point of infection14. As a fungus, C.
Cotton/Texas root rot. Cotton root rot disease is one of the most destructive and difficult to control fungal diseases that can attack more than 2,000 broadleaf plant species. Cotton growers face the threat of significant crop damage to seedlings and potential devastation near maturity.
The Irish Potato Famine was a period of starvation, disease and emigration, and was known as one of the biggest tragedies from 1845 to 1847. Many people depended on potato crops to survive; however [comma] the potato crops acquired blight, a disease that caused the potatoes to rot while still in the ground. No good crops could be grown for two years [comma] causing Irish tenant farmers unable to pay rent and was forced off their land causing over 21,000 people to die of starvation. The Irish Potato Famine caused many people to leave Ireland to seek work overseas in areas such as England and America. The Irish Potato Famine had a big impact on the history and the economy of Ireland.
Roots and tuber crops such as potato, beet, carrot, radish, parsnip and turnip have long been staple dietary components of the people of Newfoundland and Labrador. As such, diseases that affect the production of these crops have a direct impact on both the farmers and the consumers. The common scab disease is an important disease of root and tuber crops in Newfoundland. The disease is characterised by superficial or corky-like lesions that form on the surface of the crops (Figure 1). The lesions reduce the market value of the crop leading to significant economic losses for the growers. Streptomyces bacteria found in the soil are known to be the causal organisms for the common scab disease. These include Streptomyces scabies, Streptomyces turgidiscabies and Streptomyces acidiscabies (Wharton et al. 2013). In particular, S. scabies has been well documented to
The Irish Potato Famine was the worst tragedy in the history of Ireland. The outcome of the famine would result in hundreds of thousands dead, an failure of the economy in Ireland, and millions of emigrants forced to leave their home and country just to try to survive. The famine would effect countries other than Ireland as well. Some of these countries included England, America, Canada, and Australia.
The life cycle of M.graminicola is favored by optimum temperatures (15-20), and to cause infection it requires long periods of high humidity. Septoria tritici blotch survives from one season to the next on stubble. Following heavy rain or heavy dew in late autumn and early winter, wind borne spores are released from the bodies embedded in the stubble or previously infected plants. These can be spread over large distances. The Septoria tritici blotch has two very clearly visible
The genus of Alternaria can occur universally. Several species of Alternaria has been seen as contaminants in the petri-dish cultures and several laboratory media. Occasionally they can cause cutaneous infection, and also can cause chronic sinusitis. With rare cases in an immunocompromised patient, they can cause deep infections. Alternaria can grow predominately as saprophytes. They isolated and are part of the dying plants as saprobes or as pathogens and commonly found in the soil for their habitat. Alternaria can also act as a parasitic on plants. Alternaria has a group of mycotoxins, including alternariols, altertoxins, and tenuazonic acid that can cause complications in human and animals.
Sustainable management of these disease (disease complex) required an integrated disease management strategy. The integrated management can be developed by considering all the available management tool and proper execution of those strategy according to their applicability and effectiveness on the above-mentioned diseases. These foliar diseases are commonly managed by cultural practices, host resistant, biological and chemical controls. Selecting healthy and appropriately oriented vineyards, resistance or tolerance varieties or cultivars is always a good choice to prevent infection from the pathogen and development of disease epidemic. The primary infection of these pathogen can be limited by different cultural methods such as sanitation, pruning, training, burying or removal of infected crop
Like the last couple of chapters, the author begins by explaining how a winter storm destroyed many ancient paintings at Versailles and he uses this as a metaphor to compare it with a garden. Regarding disasters, this is also seen in Colorado when the Colorado potato beetle killed many potato crops and also in Ireland when a disease destroyed many of the potato crops. However, the author also describes how the use of Bt (Bacillus thuringiensis) bacteria has proved to save the Colorado potato population by being toxic to the Colorado potato beetle. In this sense, because people rely on potatoes as a good food source, they help out the potato by inserting a bacterium in its genome that will help it become resistant to pests. Unlike the three previous plants that were talked about, the potato is more susceptible to diseases because it reproduces asexually and as a result does not create much genetic diversity in its genome.
Stripe rust (Puccinia strifformis) is a fungus that weakens plants by removing water and nutrients, affecting the yield and quality of grains. Stripe rust affects wheat and can cause 100% yield losses when infection occurs early. For Example, in Washington, stripe rust affected 70% of the crops in 2002 (X. M. Chen, 2005). This disease does not just affect the United States of America, but all other countries. In China, more than 20 million ha of wheat has been affected by stripe rust(Wan, Chen, & He, 2007). This fungus spreads so fast that within a week symptoms appear and almost in two weeks, reproduction of this fungus starts to take place. More spores, mean the infection will now be able to transfer over larger areas by the means of various
America back in the 60's however had different ideas.US wanted to weaponize the fungus, either to be used in cluster bombs or spray tank. The idea was to infect the water supply causing wide crop epidemics thus starving the enemy to its knees. Thankfully, in 1960 US abandoned its desire for biological
our crops to be infected with diseases and infestations such as pests and weeds. By