NematodesBy Sam G.
First, some people spell Nematode this way; “Nematoad,” this is incorrect. A Nematode isn’t a toad or frog it’s a type of worm.
Size Microscopic Scientific Names: There are lots of Nematodes. Here are some different kinds, Plectus parvus, Plectus assimilis, Acrobeles cephalatus, Microdorylaimus angleus there are many more. The name “Nematode” comes from the Greek words: nema, which means ”thread”, and toid, which means ”form”. DescriptionNematodes are a type of roundworm in the phylum Nematoda. This is a different order of animals from the segmented worms, such as earthworms and flatworms. Nematodes are abundant, particularly in soil. Some Nematodes are plant parasitic {parasitic means it lives off from plants} and some are insect parasitic. The difference is one eats plants the other eats bugs. However, each species is usually specific in its habits. For example, insect parasitic nematodes develop only in insects. They do not grow in mammals, birds or plants. Nematodes can have many babies or eggs. Some Nematodes have 100 babies while others can have 2,000. Most Nematodes have a relatively simple lifecycle consisting of the egg, four larva stages and the male or female. Development of the first stage larvae occurs within the egg where the first molt occurs. Second stage larvae hatch from eggs to find and infect plant roots or in some cases foliar tissues. Host finding movement in soil occurs within surface films of water surrounding soil particles and root surfaces. Depending on species, feeding will occur along the root surface or in other species like root-knot, young larval stages will invade root tissue, establishing permanent feeding sites within the root. Second stage larvae will then molt three times, to become adult male or female. For most species of nematodes, as many as 50 to 100 eggs are produced per female, while others such as root-knot, up too 2,000 may be produced. Under suitable environmental conditions, the eggs hatch and new larvae emerge to complete the lifecycle within 4 to 8 weeks depending on temperature. Nematodes development is generally most rapid within an optimal soil temperature range of 70 to 80 degrees F. Nematodes are usually vermiform, long and slender, but some species are swollen. Most people know them as roundworms because their cross-section is round. They range in size from 0.08mm to 7m. Nematodes are a tube within a tube. The outer tube is the body wall, which consists of muscle layers that are used as a protective covering. The inside is the digestive system. The esophagus is the front of the digestive tube. Plant parasitic nematodes are serious pests of virtually every agricultural or ornamental Plant species grown in the United States. Regulatory and monitoring programs are necessary to prevent the introduction and spread of pest species. Currently there is not a single database or information repository that contains an exhaustive treatment of nematodes of quarantineable concern. Insect Parasitic Nematodes are small round worms that kill insects but are harmless to other organism several species of these nematodes are being developed as biological insects controls. Among the pest effectively controlled are most turf insects and several other insects that live in soil. Insect parasitic nematodes are small; round worms that complete part of their lifecycle in insects. Several species can kill insects in this process, and some are marketed as biological control agents. The use of insect parasitic nematodes to control soil insects, including many turf grass and garden pests, has received increased attention in the past few years. Insect parasitic nematodes are also known as predator nematodes, beneficial nematodes or entomogenus nematodes. They are sold under such trade names as BioSafe, Biovector, Scanmask,Exhibit, Oti-Nem and Guardian. Insect parasitic nematodes have been studied for potential biological control of turf pests for more than 50 years. However, their increasing availability and rising public demand for alternatives to insecticides has heightened interest in parasitic nematodes. Food Nematodes eat many kinds of things. Some eat plants and some eat bug larvae. One nematode eats by ripping a hole in the side of the root cells and crawls in. They move through the root piercing and sucking and leaving behind a trail of both cell-killing metabolites and eggs. Cell death results in brown lesion on the roots. Lesions begin on one side, but may encircle a root and thereby girdle it. The overall effect is a weak, shallow root system with a lot of dead areas. Insect parasitic nematodes are mobile and move short distances in search of host insects. They kill their host by releasing bacteria into it. The bacterium develops within the body cavity of the susceptible host. The host dies from blood poisoning within a few days. The host (dead) insect body usually keeps its same shape and doesn’t decay normally because its body is filled with specialized bacteria. The active stage of the nematode that invades an insect is the juvenile stage. These infective juveniles are sometimes used for insect control. Nematodes enter the bodies of the insects through their natural openings, and then penetrate into the body cavity. While they use natural body openings, they can also enter by piercing the body walls. Once they are inside the infected insect, they develop very rapidly, in five or so days, depending on host quality and temperature. Sometimes, one to two generations can occur in a host insect. Thousands of nematodes can be produced in a single infection. Eventually, the body wall of the dead insect ruptures and releases the nematodes. Insect parasitic nematodes usually kill their host insect within two or three days after invasion. Range It takes the Nematode 4 to 8 weeks to complete its lifecycle depending on the temperature. So they definitely live longer than 4 weeks. Miscellaneous
LINKS http://www.ext.colostate.edu/pubs/insect/05573.html http://www.ilscncoalition.org/ http://mgd.nacse.org/hyperSQL/squiggles/nematodes1.html http://nematode.unl.edu/wormhome.htm http://nematode.unl.edu/nemaquar/nemaquar.htm
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