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Hawthorn Rust
''Gymnosporangium globosum'' is a fungal plant pathogen that causes cedar-hawthorn rust. Hosts and symptoms ''Gymnosporangium globosum'' is a heteroecious rust fungus that requires two hosts to complete its life cycle. Its telial stage occurs on eastern red cedar, Rocky Mountain juniper, southern red cedar, and other common junipers while its aecial stage will be found on apple, crabapple, hawthorne, and occasionally on pear, quince, and serviceberry. The symptoms on the evergreens ( telial stage) start with small galls that form on its twigs and small branches. After the galls grow to be in diameter, circular indents (similar to those of a golf ball) will begin to appear on the twig side of the gall. Once spring arrives, a reddish-brown structure will begin to grow out of the indent eventually producing orange, jelly-like telial horns. These telial horns can reach up to long and can be easily seen. The symptoms of the deciduous trees (aecial stage) begin with yellow spots that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Pathogen
Plant diseases are 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, vertebrates, or other pests that affect plant health by eating plant tissues and causing injury that may admit plant pathogens. The study of plant disease is called plant pathology. Plant pathogens Fungi Most phytopathogenic fungi are Ascomycetes or Basidiomycetes. They reproduce both sexually and asexually via the production of spores and other structures. Spores may be spread long distances by air or water, or they may be soil borne. Many soil inhabiting fungi are capable of living saprotrophically, carrying out the role of their life cycle in the soil. These are facultative saprotrophs. Fungal diseases ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pruning
Pruning is the selective removal of certain parts of a plant, such as branches, buds, or roots. It is practiced in horticulture (especially fruit tree pruning), arboriculture, and silviculture. The practice entails the targeted removal of diseased, damaged, dead, non-productive, structurally unsound, or otherwise unwanted plant material from crop and landscape plants. In general, the smaller the branch that is cut, the easier it is for a woody plant to compartmentalize the wound and thus limit the potential for pathogen intrusion and decay. It is therefore preferable to make any necessary formative structural pruning cuts to young plants, rather than removing large, poorly placed branches from mature plants. Woody plants may undergo a process referred to as ''self-pruning'', where they will drop twigs or branches which are no longer producing more energy than they require. It is theorized that this process can also occur in response to lack of water, in order to reduce the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pucciniales
Rusts are fungal plant pathogens of the order Pucciniales (previously known as Uredinales) causing plant fungal diseases. An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus '' Puccinia'', are currently accepted. Rust fungi are highly specialized plant pathogens with several unique features. Taken as a group, rust fungi are diverse and affect many kinds of plants. However, each species has a range of hosts and cannot be transmitted to non-host plants. In addition, most rust fungi cannot be grown easily in pure culture. Most species of rust fungi are able to infect two different plant hosts in different stages of their life cycle, and may produce up to five morphologically and cytologically distinct spore-producing structures viz., spermogonia, aecia, uredinia, telia, and basidia in successive stages of reproduction. Each spore type is very host-specific, and can typically infect only one kind of plant. Rust fungi a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungal Tree Pathogens And Diseases
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as one of the traditional eukaryotic kingdoms, along with Animalia, Plantae, and either Protista or Protozoa and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of motility, mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the ''Eumycota'' (''true fungi'' or ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teliospore
Teliospore (sometimes called teleutospore) is the thick-walled resting spore of some fungi (Rust (fungus), rusts and Smut (fungus), smuts), from which the basidium arises. Development They develop in ''telium, telia'' (sing. ''telium'' or ''teliosorus''). The telial host is the primary host in heteroecious rusts. The aecial host is the alternate host (look for pycnium, pycnia and Aecium, aecia). These terms apply when two hosts are required by a heteroecious rust fungus to complete its life cycle. Morphology Teliospores consist of one, two or more Dikaryon, dikaryote cells. Teliospores are often dark-coloured and thick-walled, especially in species where they overwinter (acting as chlamydospores). Two-celled teliospores formerly defined the genus ''Puccinia''. Here the wall is particularly thick at the tip of the terminal cell which extends into a beak in some species. Teliospores consist of Dikaryon, dikaryote cells. As the teliospore cells germinate, the cell nucleus, nuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juniper
Junipers are coniferous trees and shrubs in the genus ''Juniperus'' ( ) of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere as far south as tropical Africa, including the Arctic, parts of Asia, and Central America. The highest-known juniper forest occurs at an altitude of in southeastern Tibet and the northern Himalayas, creating one of the highest tree lines on earth. Description Junipers vary in size and shape from tall trees, tall, to columnar or low-spreading shrubs with long, trailing branches. They are evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ... with needle-like and/or scale-like leaves. They can be either monoecious or dioecious. The female Conif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telium
Telium, plural telia, are structures produced by Rust (fungus), rust fungi as part of the reproductive cycle. They are typically yellow or orange drying to brown or black and are exclusively a mechanism for the release of teliospores which are released by wind or water to infect the alternate Host (biology), host in the rust life-cycle. The telial stage provides an overwintering strategy in the life cycle of a parasitic heteroecious fungus by producing teliospores; this occurs on cedar trees. A primary aecial stage is spent parasitizing a separate host plant which is a precursor in the life cycle of heteroecious fungi. Teliospores are released from the telia in the spring. The spores can spread many kilometers through the air, however most are spread near the host plant. Host plants There are a number of plants that can be infected by the telial stage. Therefore, the telial stage is considered a pathogen to those plants. A few specific plant pathogenic species are listed here with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnosporangium Juniperi-virginianae
''Gymnosporangium juniperi-virginianae'' is a plant pathogen that causes cedar-apple rust. In virtually any location where apples or crabapples (''Malus'') and eastern red cedar (''Juniperus virginiana'') coexist, cedar apple rust can be a destructive or disfiguring disease on both the apples and cedars. Apples, crabapples, and eastern red cedar are the most common hosts for this disease. Similar diseases can be found on quince and Crataegus, hawthorn and many species of juniper can substitute for the eastern red cedars. Symptoms On the apple tree, the infections occur on leaves, fruit and young twigs. The brightly colored spots produced on the leaves make it easy to identify. Small, yellow-orange spots appear on the upper surfaces of the leaves, anytime from April to June. These spots gradually enlarge and turn orange or red and may show concentric rings of color. Drops of orange liquid may be visible on the spots. Later in the season, black dots appear on the orange spots on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungicide
Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, including humans. Fungicides are also used to control oomycetes, which are not taxonomically/genetically fungi, although sharing similar methods of infecting plants. Fungicides can either be contact, translaminar or systemic. Contact fungicides are not taken up into the plant tissue and protect only the plant where the spray is deposited. Translaminar fungicides redistribute the fungicide from the upper, sprayed leaf surface to the lower, unsprayed surface. Systemic fungicides are taken up and redistributed through the xylem vessels. Few fungicides move to all parts of a plant. Some are locally systemic, and some move upward. Most fungicides that can be bought retail are sold in liquid form, the active ingredient being present at 0.08% i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basidium
A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also called tertiary mycelia, which are highly coiled versions of secondary mycelia. A basidium usually bears four sexual spores called basidiospores. Occasionally the number may be two or even eight. Each reproductive spore is produced at the tip of a narrow prong or horn called a sterigma (), and is forcefully expelled at full growth. The word ''basidium'' literally means "little pedestal". This is the way the basidium supports the spores. However, some biologists suggest that the structure looks more like a club. A partially grown basidium is known as a basidiole. Structure Most basidiomycota have single celled basidia (holobasidia), but some have ones with many cells (a phragmobasidia). For instance, rust fungi in the order ''Puccinal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heteroecious
A heteroecious parasite is one that requires at least two hosts. The ''primary host'' is the host in which the parasite spends its adult life; the other is the ''secondary host''. Both hosts are required for the parasite to complete its life cycle. This can be contrasted with an autoecious parasite which can complete its life cycle on a single host species. Many rust fungi have heteroecious life cycles: In parasitology, heteroxeny, or heteroxenous development, is a synonymous term that characterizes a parasite whose development involves several hosts. Fungal examples * '' Gymnosporangium'' (Cedar-apple rust): the juniper is the primary ( telial) host and the apple, pear Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus ''Pyrus'' , in the Family (biology), family Rosaceae, bearing the Pome, po ... or hawthorn is the secondary ( aecial) host. * '' C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petiole (botany)
In botany, the petiole () is the stalk that attaches the leaf blade to the Plant stem, stem. It is able to twist the leaf to face the sun, producing a characteristic foliage arrangement (spacing of blades), and also optimizing its exposure to sunlight. Outgrowths appearing on each side of the petiole in some species are called stipules. The terms wikt:petiolate, petiolate and wikt:apetiolate, apetiolate are applied respectively to leaves with and without petioles. Description The petiole is a stalk that attaches a leaf to the plant stem. In petiolate leaves the leaf stalk may be long (as in the leaves of celery and rhubarb), or short (for example basil). When completely absent, the blade attaches directly to the stem and is said to be Sessility (botany), sessile or apetiolate. Subpetiolate leaves have an extremely short petiole, and may appear sessile. The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile. In some other plant group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
