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Pythium Violae
''Pythium violae'' is a plant pathogen infecting carrots. It is a soil-borne oomycete that causes the cavity spot disease of carrots. '' Pythium sulcatum'' also causes a less serious form of this disease. ''Pythium violae'' causes elliptical shaped brown lesions surrounded by a thin yellow halo on the surface of the taproot. These lesions cause a blemished aesthetic appearance on the carrot, reducing their market value while maintaining yield. The lesions are, on average, less than half an inch in diameter and appear near harvest, but can grow as the carrot matures and grow larger on processing varieties of carrots. Low density hyphae are present in early formation of the lesions, but there is little to no presence of ''Pythium violae'' spores in the mature lesions making it difficult to diagnose in the field. This disease can be instigated by excessive rainfall, poor soil drainage, cool temperatures, and low Soil pH. ''Pythium violae'' has been shown to infect and produce similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Pathogen
Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). 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. 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. Overview Control of plant diseases is crucial to the reliable production of food, and it provides significant problems in agricultural use of land, water, fuel and other inputs. Plants in both natural and cultivated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carrot
The carrot (''Daucus carota'' subsp. ''sativus'') is a root vegetable, typically orange in color, though purple, black, red, white, and yellow cultivars exist, all of which are domesticated forms of the wild carrot, ''Daucus carota'', native to Europe and Southwestern Asia. The plant probably originated in Persia and was originally cultivated for its leaves and seeds. The most commonly eaten part of the plant is the taproot, although the stems and leaves are also eaten. The domestic carrot has been selectively bred for its enlarged, more palatable, less woody-textured taproot. The carrot is a biennial plant in the umbellifer family, Apiaceae. At first, it grows a rosette of leaves while building up the enlarged taproot. Fast-growing cultivars mature within three months (90 days) of sowing the seed, while slower-maturing cultivars need a month longer (120 days). The roots contain high quantities of alpha- and beta-carotene, and are a good source of vitamin A, vita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oomycete
Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result of contact between hyphae of male antheridia and female oogonia; these spores can overwinter and are known as resting spores. Asexual reproduction involves the formation of chlamydospores and sporangia, producing motile zoospores. Oomycetes occupy both saprophytic and pathogenic lifestyles, and include some of the most notorious pathogens of plants, causing devastating diseases such as late blight of potato and sudden oak death. One oomycete, the mycoparasite '' Pythium oligandrum'', is used for biocontrol, attacking plant pathogenic fungi. The oomycetes are also often referred to as water molds (or water moulds), although the water-preferring nature which led to that name is not true of most species, which are terrestrial pathogens. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungicide Use In The United States
This article summarizes different crops, what common fungal problems they have, and how fungicide should be used in order to mitigate damage and crop loss. This page also covers how specific fungal infections affect crops present in the United States. Almonds Alternaria leaf spot Symptoms of Alternaria leaf spot appear as lesions with tan spots on the leaves. The centers of these lesions become black with fungal sporulation. This infection can lead to tree death within 3–4 years of the first serious outbreak. Orchards in high humidity areas result in the largest yield loss, often in excess of 50%. Yield loss tends to rise every year as the tree becomes weaker each year after infection. Three fungicide applications can achieve 60–80% control of leaf spot.Specific Section 18 Emergency Exemption Request to use Azoxystrobin (Abound Flowable) to Control Alternaria on Almonds in San Joaquin Valley of California, California Department of Pesticide Regulation, 1999. Anthracnos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythium Sulcatum
''Pythium sulcatum'' is a chromalveolate Plant pathology, plant pathogen infecting carrots. Because this organism was once thought to be a type of fungus, it is still often treated as such. Host and symptoms ''Pythium sulcatum'' causes diseases predominately on members of the apiaceous family, the most common being the carrot. This pathogen causes cavity spots which are sunken, spherical to elliptical oriented, brown-black spots across the breadth of the surface of the carrot. These cavity spots are normally 1-10 mm in width and are often surrounded by a pale halo. The lesions enlarge as the roots mature, often most prominent around the time the crop is harvested. This pathogen is believed to be native of the apiaceous family that eventually became pathogenic to carrots. ''P. sulcatum'' is also seen to cause damping off, taproot dieback, root rotting, Stunt (botany), stunting, and forking of carrots, with cavity spots being the most common of these diseases. Because carrots ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lesion
A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classification or naming convention for lesions. Since lesions can occur anywhere in the body and the definition of a lesion is so broad, the varieties of lesions are virtually endless. Generally, lesions may be classified by their patterns, their sizes, their locations, or their causes. They can also be named after the person who discovered them. For example, Ghon lesions, which are found in the lungs of those with tuberculosis, are named after the lesion's discoverer, Anton Ghon. The characteristic skin lesions of a varicella zoster virus infection are called ''chickenpox''. Lesions of the teeth are usually called dental caries. Location Lesions are often classified by their tissue types or locations. For example, a "skin lesion" or a " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taproot
A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproot is a storage organ so well developed that it has been cultivated as a vegetable. The taproot system contrasts with the adventitious or fibrous root system of plants with many branched roots, but many plants that grow a taproot during germination go on to develop branching root structures, although some that rely on the main root for storage may retain the dominant taproot for centuries, for example '' Welwitschia''.Taproot also store nutrition. Plants with taproots are often vegetables. Description Dicots, one of the two divisions of flowering plants (angiosperms), start with a taproot, which is one main root forming from the enlarging radicle of the seed. The tap root can be persistent throughout the life of the plant but is most o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypha
A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or more cells surrounded by a tubular cell wall. In most fungi, hyphae are divided into cells by internal cross-walls called "septa" (singular septum). Septa are usually perforated by pores large enough for ribosomes, mitochondria, and sometimes nuclei to flow between cells. The major structural polymer in fungal cell walls is typically chitin, in contrast to plants and oomycetes that have cellulosic cell walls. Some fungi have aseptate hyphae, meaning their hyphae are not partitioned by septa. Hyphae have an average diameter of 4–6 µm. Growth Hyphae grow at their tips. During tip growth, cell walls are extended by the external assembly and polymerization of cell wall components, and the internal production of new cell membran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil PH
Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. pH is defined as the negative logarithm (base 10) of the activity of hydronium ions ( or, more precisely, ) in a solution. In soils, it is measured in a slurry of soil mixed with water (or a salt solution, such as ), and normally falls between 3 and 10, with 7 being neutral. Acid soils have a pH below 7 and alkaline soils have a pH above 7. Ultra-acidic soils (pH 9) are rare. Soil pH is considered a master variable in soils as it affects many chemical processes. It specifically affects plant nutrient availability by controlling the chemical forms of the different nutrients and influencing the chemical reactions they undergo. The optimum pH range for most plants is between 5.5 and 7.5; however, many plants have adapted to thrive at pH value ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfalfa
Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as well as a green manure and cover crop. The name alfalfa is used in North America. The name lucerne is the more commonly used name in the United Kingdom, South Africa, Australia, and New Zealand. The plant superficially resembles clover (a cousin in the same family), especially while young, when trifoliate leaves comprising round leaflets predominate. Later in maturity, leaflets are elongated. It has clusters of small purple flowers followed by fruits spiralled in 2 to 3 turns containing 10–20 seeds. Alfalfa is native to warmer temperate climates. It has been cultivated as livestock fodder since at least the era of the ancient Greeks and Romans. Etymology The word ''alfalfa'' is a Spanish modification of the Arabic word ''a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheat
Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BCE. Botanically, the wheat kernel is a type of fruit called a caryopsis. Wheat is grown on more land area than any other food crop (, 2014). World trade in wheat is greater than for all other crops combined. In 2020, world production of wheat was , making it the second most-produced cereal after maize. Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing due to the unique viscoelastic and adhesive properties of gluten proteins, which facilitate the production of processed foods, whose consumption is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broccoli
Broccoli (''Brassica oleracea'' var. ''italica'') is an edible green plant in the cabbage family (family Brassicaceae, genus ''Brassica'') whose large flowering head, stalk and small associated leaves are eaten as a vegetable. Broccoli is classified in the Italica cultivar group of the species ''Brassica oleracea''. Broccoli has large flower heads, usually dark green, arranged in a tree-like structure branching out from a thick stalk which is usually light green. The mass of flower heads is surrounded by leaves. Broccoli resembles cauliflower, which is a different but closely related cultivar group of the same ''Brassica'' species. It is eaten either raw or cooked. Broccoli is a particularly rich source of vitamin C and vitamin K. Contents of its characteristic sulfur-containing glucosinolate compounds, isothiocyanates and sulforaphane, are diminished by boiling but are better preserved by steaming, microwaving or stir-frying. Rapini, sometimes called "broccoli rabe," is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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