Nematology is the scientific discipline concerned with the study of nematodes, or roundworms. Although nematological investigation dates back to the days of Aristotle or even earlier, nematology as an independent discipline has its recognizable beginnings in the mid to late 19th century. [1] [2]
Nematology research, like most fields of science, has its foundations in observations and the recording of these observations. The earliest written account of a nematode "sighting," as it were, may be found in the Pentateuch of the Old Testament in the Bible, in the Fourth Book of Moses called Numbers: "And the Lord sent fiery serpents among the people, and they bit the people; and much people of Israel died". [3] Although no empirical data exist to test the hypothesis, many nematologists assume and circumstantial evidence suggests the "fiery serpents" to be the Guinea worm, Dracunculus medinensis , as this nematode is known to inhabit the region near the Red Sea. [2]
Before 1750, a large number of nematode observations were recorded, many by the notable great minds of ancient civilization. Hippocrates [4] (c. 420 B.C.), Aristotle [5] (c. 350 B.C.), Celsus [6] (c. 10 B.C.), Galen [7] (c. 180 A.D.) and Redi [8] (1684) all described nematodes parasitizing humans or other large animals and birds. Borellus [9] (1653) was the first to observe and describe a free-living nematode, which he dubbed the "vinegar eel;" and Tyson [10] (1683) used a crude microscope to describe the rough anatomy of the human intestinal roundworm, Ascaris lumbricoides .
Other well-known microscopists spent time observing and describing free-living and animal-parasitic nematodes: Hooke [11] (1683), Leeuwenhoek [12] (1722), Needham [13] (1743), and Spallanzani [14] (1769) are among these. [2] Observations and descriptions of plant parasitic nematodes, which were less conspicuous to ancient scientists, did not receive as much or as early attention as did animal parasites. The earliest allusion to a plant parasitic nematode is, however, preserved in famous writ. "Sowed cockle, reap'd no corn," a line by William Shakespeare penned in 1594 in Love's Labour's Lost , Act IV, Scene 3, most certainly has reference to blighted wheat caused by the plant parasite, Anguina tritici . [15]
Needham [13] (1743) solved the "riddle of cockle" when he crushed one of the diseased wheat grains and observed "Aquatic Animals...denominated Worms, Eels, or Serpents, which they very much resemble." It is likely that few or no other recorded observations of plant parasitic nematodes or their effects are to be found in ancient literature. [16]
From 1750 to the early 1900s, nematology research continued to be descriptive and taxonomic, focusing primarily on free-living nematodes and plant and animal parasites. [17] During this period a number of productive researchers contributed to the field of nematology in the United States and abroad. Beginning with Needham and continuing to Cobb, nematologists compiled and continuously revised a broad descriptive morphological taxonomy of nematodes.[ citation needed ]
Kuhn [18] (1874) is thought to be the first to use soil fumigation to control nematodes, applying carbon disulfide treatments in sugar beet fields in Germany. In Europe from 1870 to 1910, nematological research focused heavily on controlling the sugar beet nematode as sugar beet production became an important economy during this time in the Old World. [15]
Although 18th and 19th century scientists yielded a considerable amount of important fundamental and applied knowledge about nematode biology, nematology research really began to advance in quality and quantity near the turn of the 20th century. In 1918, the first permanent nematology field station was constructed in the U.S. Post Office in Salt Lake City, Utah under the direction of Harry B. Shaw, after scientists observed the sugar beet nematode in a field south of the city. [15] In this same year, Nathan Cobb (1918) published his Contributions to a Science of Nematology and his lab manual "Estimating the Nema Population of Soil." [19] These two publications provide definitive resources for many methods and apparatus used in nematology even to this day. [15]
Of Cobb's far-reaching influence on nematology research, Jenkins and Taylor [20] write:
Perhaps no one person has had as favorable an impact on the field of nematology as has Nathan Augustus Cobb.
From 1900 to 1925 various state-run agricultural experimental stations investigated important problems relating to agro-economy, though few stations devoted much attention to plant-parasitic nematodes. Accounts of the history of nematology (the few that exist) mention three major events occurring between 1926 and 1950 that affected the relative importance of nematodes in the eyes of farmers, legislators and the U.S. public in general. These same events had profound worldwide effects on the course of nematology research over the next fifty to seventy-five years.
First, the discovery of the golden nematode in the potato fields of Long Island led to a trip by U.S. quarantine officials to the potato fields of Europe, where the devastating effects of this parasite had been known for many years. This excursion allayed all skepticism about the seriousness of this agricultural pest. Second, the introduction of the soil fumigants, D-D and EDB made available for the first time nematicides that could be used effectively and practically on a field scale. Third, the development of nematode-resistant crop cultivars brought substantial government funding to applied nematology research. [15] [17] [21]
These events contributed to a shift from broad taxonomy-based nematology research to deep, yet focused investigations of plant parasitic nematodes, especially the control of agricultural pests. From the early 1930s until recently, the bulk of researchers studying nematodes have been plant pathologists by training. [17] Consequently, nematological research leaned heavily toward answering plant pathological and agro-economical questions for the last three-quarters of the 20th century.[ citation needed ]
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Nematologists in the 1800s also contributed to other scientific fields in important ways. Butschli [22] (1875) first observed the formation of polar bodies by nuclear subdivision in a nematode, Beneden [23] (1883) was studying Ascaris megalocephala when he discovered the separation of halves of each of the chromosomes from the two parents and the mechanism of Mendelian heredity, and Boveri [24] (1893) showed evidence for continuity of the germ plasm and that the soma may be regarded as a by-product without influence upon heredity. [2]
Caenorhabditis elegans is a widely used model species, initially for neural development, and then for genetics. WormBase collates research on the species.[ citation needed ]
Nathan Augustus Cobb is known as "the father of nematology in the United States".
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.
Root-knot nematodes are plant-parasitic nematodes from the genus Meloidogyne. They exist in soil in areas with hot climates or short winters. About 2000 plants worldwide are susceptible to infection by root-knot nematodes and they cause approximately 5% of global crop loss. Root-knot nematode larvae infect plant roots, causing the development of root-knot galls that drain the plant's photosynthate and nutrients. Infection of young plants may be lethal, while infection of mature plants causes decreased yield.
Ascaris is a nematode genus of parasitic worms known as the "small intestinal roundworms", which is a type of parasitic worm. One species, Ascaris lumbricoides, affects humans and causes the disease ascariasis. Another species, Ascaris suum, typically infects pigs. Other ascarid genera infect other animals, such as Parascaris equorum, the equine roundworm, and Toxocara and Toxascaris, which infect dogs and cats.
Parasitic worms, also known as helminths, are large macroparasites; adults can generally be seen with the naked eye. Many are intestinal worms that are soil-transmitted and infect the gastrointestinal tract. Other parasitic worms such as schistosomes reside in blood vessels.
Pratylenchus brachyurus is a plant parasitic nematode.
Heterodera schachtii, the beet cyst eelworm or sugarbeet nematode, is a plant pathogenic nematode. It infects more than 200 different plants including economically important crops such as sugar beets, cabbage, broccoli, and radish. H. schachtii is found worldwide. Affected plants are marked by stunted growth, wilting, yellowing, decreased yields, and death. While there are many methods of control, crop rotation with non-susceptible plants is preferred.
Xiphinema americanum, the American dagger nematode, is a species of plant pathogenic nematodes. It is one of many species that belongs to the genus Xiphinema. It was first described by N. A. Cobb in 1913, who found it on both sides of the United States on the roots of grass, corn, and citrus trees. Not only is Xiphinema americanum known to vector plant viruses, but also X. americanum has been referred to as "the most destructive plant parasitic nematode in America", and one of the four major nematode pests in the Southeastern United States.
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.
The nematodes, roundworms or eelworms constitute the phylum Nematoda. They are a diverse animal phylum inhabiting a broad range of environments. Most species are free-living, feeding on microorganisms, but there are many that are parasitic. The parasitic worms (helminths) are the cause of soil-transmitted helminthiases.
Mermithidae is a family of nematode worms that are endoparasites in arthropods. As early as 1877, Mermithidae was listed as one of nine subdivisions of the Nematoidea. Mermithidae are confused with the horsehair worms of the phylum Nematomorpha that have a similar life history and appearance.
Human parasites include various protozoa and worms.
Mohammad Shamim Jairajpuri was an Indian zoologist. He served as a professor and Chairman of the Zoology Department and Dean of the Faculty of Life Sciences at Aligarh Muslim University Aligarh before retirement in 2004. He received the first Janaki Ammal National Award bestowed by the Government of India, Ministry of Environment & Forests and Lifetime Achievement Award from the Zoological Society of India for his notable works on taxonomy of nematodes (1964–2004).
Michel Luc was a French zoologist (nematologist) and one of the founding fathers of the field of plant-nematology. He spent his career with ORSTOM, now IRD. He created the first French nematology laboratory in the ORSTOM research station of Adiopodoumé, near Abidjan in 1955, and a second nematology lab at Dakar Bel-Air (Senegal) in 1969. In 1978, he launched the Revue de Nématologie that fused with Nematologica in 1999 to become Nematology, currently the leading nematology journal in the field. He was a world-renowned authority on nematode taxonomy.
Trichodoridae is a family of terrestrial root feeding nematodes, being one of two that constitute suborder Triplonchida. They are economically important plant parasites and virus vectors.
Johannes Hallmann is a German agricultural scientist of phytomedicine. He is a scientific adviser at the Julius Kühn-Institut, the Federal Research Institute for Cultivated Plants, the Institute for Epidemiology and Pathogen Diagnostics in Münster, the University Professor for Nematology and the President of the German Phytomedicine Society.
István Andrássy was a Hungarian nematologist. Starting with his first publication in 1952 on the nematode fauna of Mount Bükk, over his dissertation in 1973 on the evolution of nematodes to his last days he was a very prolific scientist, publishing more than 200 manuscripts, chapters and books on the class of Nematoda. He described 530 taxa of nematodes and at least 60 nematode taxa are named after him, which shows the huge respect he had in the nematologists world.
May Belle Hutson Chitwood was an American author, nematologist, helminthologist, and zoologist at the Agricultural Research Service, curator of the National Parasite Collection, and director of the primate parasite registry at University of California at Davis. Chitwood specialized in the morphology of nematodes early in the research of this aspect of the species, and was considered a world authority. She published over 50 research papers about nematology, helminthology, and zoology.
Jesse Roy Christie was an American nematologist and plant pathologist.
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.
