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Nematology at Cornell

A History, by W.F. Mai

Bill Mai

Cornell Professor Emeritus William F. Mai in 1957.
(image CUP 44129a).

(page 1, 2, 3, 4, 5, 6, 7)

Although the history of mycology at Cornell has been described by a number of mycologists, a writeup of plant nematology at Cornell has not been located. Thus I decided to write one.

In an introduction some of the significant developments in nematology from 2700 B.C. to the present are mentioned. The following items are included in a history of plant nematology in New York State and Cornell.

First publications on plant nematology at Cornell were by Newhall and Chitwood in 1940 and Newhall in 1942. Some of the first records of the occurrence of plant parasitic nematodes in New York State were by H. H. Whetzel in 1903 and 1905. Since the publication by Newhall and Chitwood there have been 195 refereed publications in plant nematology at Cornell. In addition approximately 90 abstracts have been published. As well as around 50 miscellaneous publications.

The first formal instruction in plant nematology was by Mai in 1955 as a part of Advanced Plant Pathology (201). This course also included instruction in plant virology by Ross and plant bacteriology by Burkholder. The nematology instruction lasted for approximately 4 weeks. In 1956-57 Mai first offered a 2 credit-hour course in plant nematology.

Research experiments have been conducted in 40 research projects in a variety of areas. Research has been conducted on a number of different kinds of plant pathogenic nematodes including the stem and bulb nematode of onions (Ditylenchus dipsaci), the golden nematode of potatoes (Heterodera rostochiensis), nematodes attacking roots of fruit trees (primarily Pratylenchus penetrans) nematodes attacking roots of vegetables and nursery crops (Meloidogyne hapla and others), and a cyst nematode attacking table beets and cabbage

Heterodera schachtii. Most of the studies have been conducted on plant parasitic nematodes but other soil-inhabiting nematodes and other soil inhabiting organisms have been included in the tests. Chemical control has received major attention but other control measures have been emphasized in recent years. Although nematode control has been emphasized other areas have been studied - such as nematode physiology, taxonomy, morphology, and life cycles; nematode population dynamics; relationships with other organisms and nematode-plant relationships.

From 1947 to 1996, 42 Ph.D. and 25 M.S. degrees were granted in plant pathology with special emphasis in plant nematology at Cornell. According to an informal survey by Ken Barker of North Carolina State during a 15 year or so period in the 1960s and 1970s more Ph.D.'s in plant nematology were granted at Cornell than at any other university. Also the students receiving these degrees published more papers than students from any other university. At least 20 of the students granted degrees at Cornell are now teaching plant nematology at universities.

Although it was not possible to locate the addresses of all former students in plant nematology more than 50 were located and recorded.

The substantial contributions of Louis Hsu in accumulating and organizing information published in this writeup are greatly appreciated. Without the excellent word processing of Mary Brodie the final copy would not have been possible. The importance of this contribution is here recognized.

Plant Nematology at Cornell University

Large animal parasites, usually human parasites visible to the human eye, were mentioned in the literature about 2,000 years ago. Dr. Armand Maggenti gave an excellent account of the early history of nematodes in his book "General Nematology" written in 1981. Most of the information on early history included in this writeup came from this book. Written references to nematodes were recovered from literature of the civilizations of the Mediterranean Middle East, and Orient. The oldest reference to parasitic nematodes was found in Huang Ti Nei Ching or The Yellow Emperor's Classic of Internal Medicine from China ca. 2700 B.C. This account is quite detailed in that it indicates food to be avoided as well as symptomatology and treatment for problems caused by human parasites.

Some of the early references to nematodes are found in the Bible. Some interpret the passages of Moses relating to Hebrew Laws of sanitation and hygiene as emanating from early information from Egyptian physicians about parasites. The reference to the fiery serpent and the technique to remove this pest from tissues by winding it around a stick were also mentioned. This method of extraction is still practiced in many parts of North Africa and the Middle East.

It is notable that Hypocrates, ca 430 BC was aware of nematodes as parasites and was probably the first to record knowledge of the pinworm. He mentioned the presence of pinworms in the vagina of women and of similar organisms in horses, the latter being the first observation in domestic animals.

Aristotle also knew of nematodes as parasites especially Ascaris. He stated "these intestinal worms do not propagate their kind." This supported the theory of "spontaneous generation" which had such a disastrous influence on science which was in a dark age for almost 2000 years. A few of the isolated advances during this period were: Celsus (53 B.C.7 A.D.) distinguished roundworms from flat worms; Columella, ca. 100 A.D., mentioned an Ascarid from a calf; Galen (130-200 A.D.) recorded nematodes in fish and Albertus Magnus (1200-1280) A.D. recorded nematodes from birds, namely, falcons.

The sixteenth century marked a reawakening of sciences, but discoveries were still 50-100 years apart. As Chitwood stated: "the period from the 16th century to the 18th century may be regarded as the medieval period of this subject."

Importance of the microscope. The most important contribution to the advancement of nematology was the microscope. Tyson (1683) studied nematode anatomy and described a nematode egg. Borellus (1656) discovered the first free-living nematode. In 1743 Needham discovered the first free-living nematode in wheat (Anguina tritici).

Development of Plant Nematology. There was important progress in nematology in the 19th Century. Significant to the growth and recognition of plant nematology was the introduction of sugar beets into Europe. Soon after its introduction there were economic losses to this crop. The condition was not attributed to nematodes but to "beet-tired soil."

In 1959 in Germany, Schacht discovered that the decline in beet production was always associated with a cyst-forming nematode now recognized as Heterodera. However, the nematode was not accepted as the causal agent for some time and was first described and named by Schmidt in 1871. The name became Heterodera schachtii after the original discoverer. During this period, the potato cyst nematode was first observed, but not recognized as a separate species. At first all the potato cyst nematodes were named Heterodera rostochiensis. At present these nematodes are divided into the species rostochiensis and pallida, and the genus name has been changed to Globodera. Soon after the potato cyst nematode was found in the United States it caused severe economic losses in a number of potato fields on Long Island, New York. This was significant to the recognition and growth of plant nematology in the United States.

Experiments to control plant nematodes dominated plant nematological research in Europe from 1870-1910. A control developed for sugar beet nematode, crop rotation, is still used. The first trials to control nematodes with soil fumigation were made by Kühn also studied the use of trap crops to control nematodes. This control measure has never been widely used.

Relatively easily observed root knot nematodes were first recognized in 1855 when they were discovered by Berkeley on cucumbers in an English greenhouse. This discovery was important because it led to recognition of other plant parasitic nematodes.

History and development in America. Root knot nematodes, Meloidogyne spp. were the first plant parasitic species observed in the United States and these were recorded by May in 1888. Working independently, Atkinson in Alabama and Neal in Florida made extensive studies on the morphology, host ranges and crop damage of these nematodes and in 1889 both published the results of their investigations.

In 1892 George Atkinson joined the staff of Cornell University, succeeding W.R. Dudley. He was designated assistant cryptogamic botanist with half time devoted to diseases of plants. In 1896, on the death of A.N. Prentiss, Atkinson succeeded to the chair in Botany in the University and thereby became botanist in the Experiment Station. The position of cryptogamic botanist was not filled and Professor Atkinson continued alone to work on plant diseases. He published many important papers on plant diseases caused by organisms other than nematodes, particularly fungi. No records were discovered to indicate that Atkinson continued his working on plant nematodes or diseases caused by them at Cornell.

Halstead in New Jersey (1891) and Stone and Smith in (1898) published additional observations on root knot and from that time on numerous workers published on root-knot nematodes. Root knot was recorded in neighboring states to New York in the late 19th century. Thus these nematodes were undoubtedly present in New York State. In Neal's paper he notes that, although not recognized by the scientific community, the presence of root knot in Florida extended back as far as the early Spanish explorers. Thus they were probably in other areas of the United States that early.

There were several reports of root knot occurring on plant roots in New York during the early 19th century, including reports by H.H. Whetzel in 1903 and 1905. No reports of research on nematodes or nematode induced diseases by Cornell staff members were found until papers published by A.G. Newhall in 1940 and 1942. The paper in 1940 coauthored with B.G. Chitwood was entitled:

Newhall, A.G. and Chitwood, B.G. 1940. Onion eel-worm or bloat caused by the stem or bulb nematode Ditylenchus dipsaci. Phytopathology 30:390-400.

The 1942 publication was entitled:

Newhall, A.G. 1942. Chloropicrin and ethylene dichloride for root-knot nematode control. Phytopathology 32:626-630.

Soon after the potato cyst (golden) nematode was found in the United States in 1941 it caused severe economic losses in a number of potato fields on Long Island, New York. New York State and the United States Department of Agriculture initiated programs to control this nematode. The emphasis on controlling the potato cyst nematode increased the development of plant nematology in the Department of Plant Pathology at Cornell. This intensive cooperative program drastically limited the spread of the golden nematode and thus permitted the continued economic production of potatoes in all potato-growing areas of the United States. It has been referred to as one of the most comprehensive pest management programs ever carried out.

B.G. Chitwood of the USDA, stationed on Long Island, identified the golden nematode to species and conducted the initial research on this nematode on Long Island. In cooperation with a number of Cornell graduate students and technicians W.F. Mai, B. Lear and M. Harrison did considerable research on numerous facets of this problem. A number of USDA staff members including V. Dropkin, G. Fassuliotis, J. Feldmesser, and F.J. Spruyt also conducted considerable research on this problem. In 1969 B. Brodie was transferred from Tifton, Georgia to Cornell to conduct research on this problem. For 29 years Bill directed a high percent of the research on this problem. His results have been very important in delaying the spread of this nematode.

At approximately the same time interest in plant nematology was increasing in other parts of the USA and in other parts of the world. One of the major reasons for this increased interest was the discovery and development of practical nematicides such as DD, Ethylene Dibromide, and Nemagon suitable for use under field conditions. Thus for the first time it was possible to demonstrate the severe damage caused by nematodes and the tremendous yield increases and increased profits that could be obtained by the application of a nematicide. A major objective of current research in plant nematology is to develop other than chemical controls to duplicate the spectacular yield increases and profits obtained by chemical treatments.

More Cornell Nematology History :


(page 1, 2, 3, 4, 5, 6, 7)