Plant pathology is the scientific study of diseases in plants caused by pathogens and environmental conditions. Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are ectoparasites like insects, mites, vertebrate, or other pests that affect plant health by eating plant tissues and causing injury that may admit plant pathogens. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases.
A pest is any organism harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environment for their own purposes and are intolerant of other creatures occupying the same space when their activities impact adversely on human objectives. Thus, an elephant is unobjectionable in its natural habitat but a pest when it tramples crops.
Central Saanich is a district municipality in Greater Victoria, British Columbia, Canada, and a member municipality of the Capital Regional District. It is located on the Saanich Peninsula, in the far south-east of Vancouver Island. It is the traditional territory of the W̱SÁNEĆ people. The district began as a farming community, and many hobby farms, along working farms and vineyards, still exist. In recent decades, the area has seen increasing residential, commercial, and industrial development, especially around the neighbourhoods of Brentwood Bay and Saanichton, which are occasionally referred to as separate communities.
Dr. Maynard Jack "Doc" Ramsay was an American entomologist noted for his efforts to track and eradicate exotic parasites carried in flowers, fruits and other cargoes arriving from overseas. He was listed in American Men of Science and Who's Who in America.
The soybean cyst nematode (SCN), Heterodera glycines, is the most devastating pest to soybean crop yields in the U.S., targeting the roots of soybean and other legume plants. When infection is severe SCNs cause stunting, yellowing, impaired canopy development, and yield loss. The symptoms caused by SCNs can go easily unrecognized by farmers—in some cases there are no warning symptoms before a loss of 40% of the yield. Due to the slight stunting and yellowing, many farmers may mistake these symptoms as environmental problems when in fact they are SCNs. Another symptom of SCNs that may affect farmers' yields is stunted roots with fewer nitrogen-fixing nodules. Due to the fact that soybean cyst nematodes can only move a few centimeters in the soil by themselves, they mostly are spread via tillage or plant transplants. This area of infection will look patchy and nonuniform making diagnosis more difficult for farmers. They can be seen in the roots of summer soybean plants if the roots are taken out very carefully and gently washed with water. The egg masses should be seen as bright white or yellow "pearls" on the roots. The later the roots are pulled the harder it will be to diagnose due to the SCNs female dying and turning a much darker color, forming a "cyst". The best way to know if a field is infected by soybean cyst nematodes is to take a soil sample to a nematologist.
Potato root nematodes or potato cyst nematodes (PCN) are 1-mm long roundworms belonging to the genus Globodera, which comprises around 12 species. They live on the roots of plants of the family Solanaceae, such as potatoes and tomatoes. PCN cause growth retardation and, at very high population densities, damage to the roots and early senescence of plants. The nematode is not indigenous to Europe but originates from the Andes. Fields are free from PCN until an introduction occurs, after which the typical patches, or hotspots, occur on the farmland. These patches can become full field infestations when unchecked. Yield reductions can average up to 60% at high population densities.
Pratylenchus penetrans is a species of nematode in the genus Pratylenchus, the lesion nematodes. It occurs in temperate regions worldwide, regions between the subtropics and the polar circles. It is an animal that inhabits the roots of a wide variety of plants and results in necrotic lesions on the roots. Symptoms of P. penetrans make it hard to distinguish from other plant pathogens; only an assay of soil can conclusively diagnose a nematode problem in the field. P. penetrans is physically very similar to other nematode species, but is characterized by its highly distinctive mouthpiece. P. penetrans uses its highly modified mouth organs to rupture the outer surface of subterranean plant root structures. It will then enter into the root interior and feed on the plant tissue inside. P. penetrans is considered to be a crop parasite and farmers will often treat their soil with various pesticides in an attempt to eliminate the damage caused by an infestation. In doing this, farmers will also eliminate many of the beneficial soil fauna, which will lead to an overall degradation of soil quality in the future. Alternative, more environmentally sustainable methods to control P. penetrans populations may be possible in certain regions.
Ditylenchus destructor is a plant pathogenic nematode commonly known as the potato rot nematode. Other common names include the iris nematode, the potato tuber eelworm and the potato tuber nematode. It is an endoparasitic, migratory nematode commonly found in areas such as the United States, Europe, central Asia and Southern Africa.
Globodera pallida is a species of nematode in the family Heteroderidae. It is well known as a plant pathogen, especially of potatoes. It is "one of the most economically important plant parasitic nematodes," causing major crop losses, and is a model organism used to study the biology of cyst nematodes. Its common names include potato cyst nematode, white potato cyst nematode, pale potato cyst nematode, potato root eelworm, golden nematode, and pale cyst nematode.
Heterodera carotae is a plant pathogenic nematode commonly known as the carrot root nematode or carrot cyst nematode. It is found in Europe, Cyprus and India and is considered an invasive species in the United States. It causes damage to carrot crops and is very specific in its choice of hosts, only infecting Daucus carota and Daucus pulcherrima.
Heterodera sacchari, the sugarcane cyst nematode, mitotic parthenogenic sedentary endoparasitic nematode. This plant-parasitic nematode infects the roots of sugarcane, and the female nematode eventually becomes a thick-walled cyst filled with eggs. Aboveground symptoms are species specific and are similar to those caused by other Heterodera species. Symptoms include: stunted and chlorotic plants, and reduced root growth. Seedlings may be killed in heavily infested soils.
Lana Popham is a Canadian politician representing the riding of Saanich South in the Legislature of British Columbia. As a member of the British Columbia New Democratic Party, she has served in the Executive Council since 2017, currently as the Minister of Tourism, Arts, Culture and Sport. She was first elected in the 2009 provincial general election to the 39th Parliament and then re-elected in 2013, 2017 and 2020 to the 40th, 41st and 42nd Parliaments.
Globodera tabacum, commonly known as a tobacco cyst nematode, is a plant parasitic nematode that mainly infests the tobacco plant, but also plants in family Solanaceae.
Plant Protection and Quarantine (PPQ) is one of six operational program units within the Animal and Plant Health Inspection Service (APHIS) of the United States Department of Agriculture (USDA). The PPQ works to safeguard agriculture and natural resources in the U.S. against the entry, establishment, and spread of animal and plant pests, and noxious weeds in order to help ensure the protection of native flora and an abundant, high-quality, and varied food supply.
Pratylenchus alleni is a migratory endoparasitic nematode, living inside of plant roots and feeding on parenchyma cells in the root cortex. P. alleni is an obligate biotroph, meaning it must have a living host in order to survive. Due to their incredibly broad host range, Pratylenchus species fall third in total economic impact, finishing just behind cyst nematodes and root knot nematodes (Meloidogyne). In Canada, it was isolated for the first time in 2011 in a soybean field.
Globodera ellingtonae is one of the potato cyst nematodes and was recently recognized as a new species in the United States. This triggered a quarantine of the fields where it was isolated to prevent the spread of this nematode to other fields.
Maris Piper is the most widely grown potato variety in the United Kingdom accounting for 16% of the planted area in 2014. Introduced in 1966 it was one of the first potato varieties bred to be resistant to a form of potato cyst nematode, a major pest of potato production in the UK. It has been the most widely grown variety in the UK since 1980 and is suitable for a range of uses including chips, roast potatoes and mashed potatoes.
Benjamin Goodwin Chitwood was an American zoologist and pioneer in nematology. He published extensively and broadly in the field of nematology. An Introduction to Nematology, published with his wife May Belle Hutson Chitwood, was a major contribution to the field. Chitwood identified the species Globodera rostochiensis on Long Island in 1941 and as part of his work on higher classification revised the taxonomy of the root-knot nematode Meloidogyne incognita in 1949. This led to changes in research and control strategies for it. He served as president of the Helminthological Society of Washington in 1949 and was made a Life Member of the Society in 1968.
Joshua Sikhu Okonya is a Ugandan Author and an International agricultural research scientist. He is an Agronomist and a scholar who has made contributions to the body of knowledge in agriculture and the adaptation of African agricultural systems to climate change.
