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Beech Bark Disease
Beech bark disease is a disease that causes mortality and defects in beech trees in the eastern United States, Canada and Europe.Houston, David R., and James T. O'Brien. "Beech Bark Disease." Forest Insect and Disease Leaflet 75(1998) 1-7. 17 Mar 2008 . Tainter, Frank H., and Fred A. Baker . Principles of Forest Pathology. New York, NY: John Wiley & Sons, Inc., 1996.Sinclair, Wayne A., and Howard H. Lyon. Diseases of Trees and Shrubs. 2nd ed. Ithaca, NY: Cornell University Press, 2005. In North America, the disease occurs after extensive bark invasion by '' Xylococculus betulae'' and the beech scale insect, '' Cryptococcus fagisuga''. Through a presently unknown mechanism, excessive feeding by this insect causes two different fungi (''Neonectria faginata'' (previously ''Nectria coccinea var. faginata'') and '' Neonectria ditissima'' (previously ''Nectria galligena'')) to produce annual cankers on the bark of the tree. The continuous formation of lesions around the tree eventuall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neonectria Faginata
''Neonectria faginata'' is a species of fungi that affects ''Beech'' trees in North America. Neonectria faginata, along with ''Neonectria ditissima'', are the cause of beech bark disease in trees that have already been affected by beech scale ''Cryptococcus fagisuga''. References {{Taxonbar, from=Q49630882 Nectriaceae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fagus Grandifolia
''Fagus grandifolia'', the American beech or North American beech, is a species of beech tree native to the eastern United States and extreme southeast of Canada. Description ''Fagus grandifolia'' is a large deciduous tree growing to tall, with smooth, silver-gray bark. The leaves are dark green, simple and sparsely-toothed with small teeth that terminate each vein, long (rarely ), with a short petiole. The winter twigs are distinctive among North American trees, being long and slender ( by ) with two rows of overlapping scales on the buds. Beech buds are distinctly thin and long, resembling cigars; this characteristic makes beech trees relatively easy to identify. The tree is monoecious, with flowers of both sexes on the same tree. The fruit is a small, sharply-angled nut, borne in pairs in a soft-spined, four-lobed husk. It has two means of reproduction: one is through the usual dispersal of seedlings, and the other is through root sprouts, which grow into new trees. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symptoms
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showing on a medical scan. A symptom is something out of the ordinary that is experienced by an individual such as feeling feverish, a headache or other pain or pains in the body. Signs and symptoms Signs A medical sign is an objective observable indication of a disease, injury, or abnormal physiological state that may be detected during a physical examination, examining the patient history, or diagnostic procedure. These signs are visible or otherwise detectable such as a rash or bruise. Medical signs, along with symptoms, assist in formulating diagnostic hypothesis. Examples of signs include elevated blood pressure, nail clubbing of the fingernails or toenails, staggering gait, and arcus senilis and arcus juvenilis of the eyes. Indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a census, a process of collecting, analysing, compiling, and publishing data regarding a population. Perspectives of various disciplines Social sciences In sociology and population geography, population refers to a group of human beings with some predefined criterion in common, such as location, Race (human categorization), race, ethnicity, nationality, or religion. Demography is a social science which entails the statistical study of populations. Ecology In ecology, a population is a group of organisms of the same species who inhabit the same particular geographical area and are capable of Sexual reproduction, interbreeding. The area of a sexual population is the area where interbreeding, inter-breeding is possible between any pai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spores
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa. Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions. Myxozoan spores release amoeboid infectious germs ("amoebulae") into their hosts for parasitic infection, but also reproduce within the hosts through the pairing of two nuclei within the plasmodium, which develops from the amoebula. In plants, spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to form a zygote which develops into a new s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molt
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer layer or covering), either at specific times of the year, or at specific points in its life cycle. In medieval times it was also known as "mewing" (from the French verb "muer", to moult), a term that lives on in the name of Britain's Royal Mews where the King's hawks used to be kept during moulting time before becoming horse stables after Tudor times. Moulting can involve shedding the Epidermis (skin), epidermis (skin), pelage (hair, feathers, fur, wool), or other external layer. In some groups, other body parts may be shed, for example, the entire exoskeleton in arthropods, including the wings in some insects. Examples In birds In birds, moulting is the periodic replacement of feathers by shedding old feathers while producing new o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antenna (biology)
Antennae ( antenna), sometimes referred to as "feelers", are paired appendages used for Sensory system, sensing in arthropods. Antennae are connected to the first one or two Segmentation (biology), segments of the arthropod head. They vary widely in form but are always made of one or more jointed segments. While they are typically sensory organs, the exact nature of what they sense and how they sense it is not the same in all groups. Functions may variously include sensing tactition, touch, air motion, heat, vibration (sound), and especially insect olfaction, smell or gustation, taste. Antennae are sometimes modified for other purposes, such as mating, brooding, swimming, and even anchoring the arthropod to a substrate (biology), substrate. Larval arthropods have antennae that differ from those of the adult. Many crustaceans, for example, have free-swimming larvae that use their antennae for swimming. Antennae can also locate other group members if the insect lives in a group, lik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nymphs
A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typically tied to a specific place or landform, and are usually depicted as maidens. They were not necessarily immortal, but lived much longer than human beings. They are often divided into various broad subgroups, such as the Meliae (ash tree nymphs), the Dryads (oak tree nymphs), the Naiads (freshwater nymphs), the Nereids (sea nymphs), and the Oreads (mountain nymphs). Nymphs are often featured in classic works of art, literature, mythology, and fiction. Since the Middle Ages, nymphs have been sometimes popularly associated or even confused with fairies. Etymology The Greek word has the primary meaning of "young woman; bride, young wife" but is not usually associated with deities in particular. Yet the etymology of the noun rema ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parthenogenetic
Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development of embryos occur in a gamete (egg or sperm) without combining with another gamete (e.g., egg and sperm fusing). In animals, parthenogenesis means development of an embryo from an unfertilized egg cell. In plants, parthenogenesis is a component process of apomixis. In algae, parthenogenesis can mean the development of an embryo from either an individual sperm or an individual egg. Parthenogenesis occurs naturally in some plants, algae, invertebrate animal species (including nematodes, some tardigrades, water fleas, some scorpions, aphids, some mites, some bees, some Phasmatodea and parasitic wasps) and a few vertebrates (such as some fish, amphibians, reptiles and birds). This type of reproduction has been induced artificially in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stylet (anatomy)
A stylet is a hard, sharp, anatomical structure found in some invertebrates. For example, the word ''stylet'' or stomatostyle is used for the primitive piercing mouthparts of some nematodes and some nemerteans. In these groups the stylet is a hardened protrusible opening to the stomach. These stylets are adapted for the piercing of cell walls and usually function by providing the operative organism with access to the nutrients contained within the prey cell. The mouthparts of tardigrades, diptera and aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...s are also called stylets. In octopodes, the stylets are internal, needle-like bent rods within the mantle, the vestigial remnants of an external shell. References Nematode anatomy {{Animal-anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beech Scale Insects
Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engleriana'' subgenus is found only in East Asia, distinctive for its low branches, often made up of several major trunks with yellowish bark. The better known ''Fagus'' subgenus beeches are high-branching with tall, stout trunks and smooth silver-grey bark. The European beech (''Fagus sylvatica'') is the most commonly cultivated. Beeches are monoecious, bearing both male and female flowers on the same plant. The small flowers are unisexual, the female flowers borne in pairs, the male flowers wind-pollinating catkins. They are produced in spring shortly after the new leaves appear. The fruit of the beech tree, known as beechnuts or mast, is found in small burrs that drop from the tree in autumn. They are small, roughly triangular, and edible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
