Importance Of Nematology

By:- Bijaya Lakshmi Nongmaithem & Ajit Kumar Ngangbam *

INTRODUCTION

Nematodes are a diverse group of roundworms that occur worldwide in virtually every environment. 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".

Although no empirical data exists 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.

Before 1750, a large number of nematode observations were recorded, many by the notable great minds of ancient civilization. Hippocrates (ca. 420 B.C.), Aristotle (ca. 350 B.C.), Celsus (ca 10 B.C.), Galen (ca. 180 A.D.) and Redi (1684) all described nematodes parasitizing humans or other large animals and birds.

Borellus (1653) was the first to observe and describe a free-living nematode, which he dubbed the "vinegar eel;" and Tyson (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 (1683), Leeuwenhoek (1722), Needham (1743), and Spallanzani (1769) are among these. Observations and descriptions of plant parasitic nematodes, which were less conspicuous to ancient scientists, didn't 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 Labour's Lost', Act IV, Scene 3, most certainly has reference to blighted wheat caused by the plant parasite, Anguina tritici. Needham (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. From 1750 to the early 1900's, nematology research continued to be descriptive and taxonomic, focusing primarily on free-living nematodes and plant and animal parasites.

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.

IMPORTANCE OF NEMATOLOGY

Nematodes are second only to insects in the number of species in the animal kingdom. However, only about 3 percent of all nematode species have been studied and identified. One cubic foot of soil may contain millions of individual nematodes belonging to several different taxonomic groups.

Some of the best known nematodes are animal parasites such as heartworms, pinworms, and hookworms. Another important group of nematodes parasitize plants, which results in an estimated $8 billion a year loss to U.S. agriculture, and nearly $78 billion loss worldwide.

Often, plant damage caused by nematodes is overlooked because the resulting nonspecific symptoms, such as slow growth, stunting, and yellowing, can also be attributed to nutritional and water-associated disorders.

Many nematode species are beneficial to agricluture and the environment. For example, some have proven to be important allies in the biological control of insects and other pests, and some contribute to soil fertility by helping cycle nutrients through the soil.

Nematologists understand the critical need to develop ecologically sound and sustainable farming practices that protect soil, water, and human health. Nematologists at many different research institutions across the U.S., including the University of Florida, North Carolina State University, University of Georgia, Iowa State University, Michigan State University, and others, are working to establish a strong scientific foundation in nematode biology and management.

The Society of Nematologists is a national scientific organization that fosters communication among nematologists. The remainder of this document provides a short history of nematology in the U.S., but emphasizes the development of nematology in California. Since nematodes plays an important role in agriculture and other related activities. The research on this field will directly benefits humanity greatly enhances our understanding of the earth biodiversity and is going to be an exciting challenge in the years to come.

The importance of nematodes especially in agricultural productivity was realized only during the Second World War. In India the 1960's were considered as the most active phase of nematology. Inspite of the vast knowledge regarding the harms and control aspects of parasitic nematodes, there are lacunae in the emerging areas of nematode problems.

There is used for transferring various technologies developed for nematode management to the ultimate end users, acquainting the policy makers about the importance of nematodes and strengthening nematode identification centres. Parasitic nematodes causes heavy losses to agricultural production and public health in India and developing countries of the world.

Most nematodes feed on bacteria, fungi, or other microscopic creatures. As such, they are a major component of soil and sediment ecosystems. One species that feeds on soil bacteria, Caenorhabditis elegans, has gained fame as a research model. Three specialists on the biology of this worm were the 2002 recipients of the Nobel prize in Medicine.

A small fraction of all nematode species are parasites of humans, livestock or agricultural crops. Consequently, these have attracted the most attention from Nematology researchers.

For example, root-knot, cyst and lesion nematodes are pests of a wide variety of crops and are annually responsible for billions of dollars of crop losses. Well known animal parasites with health and economic impact include pinworms, hookworms, trichina and dog heartworm.

CONCLUSION

Research on nematodes directly benefits humanity, greatly enhances our understanding of the Earth's biodiversity. Large amounts of nematicides are still being used. Since the use of traditional nematicides must be reduced, there is an increasing demand for alternatives.

Studies on biological control as a possible alternative included in an Integrated Pest management deserve and get attention in an International context. There is a growing need for researchers experienced in physiological and molecular techniques, e.g. the development of monoclonal antibodies and genetic manipulation. In the future also in environmental studies the demand for nematologists will be increasing.

Nowadays we look upon nematodes as a very successful class of animals. Four out of five multi-cellular animals on earth are nematodes.

They're present almost everywhere: in cultivated fields, in sand dunes, in the sediments beneath the Ocean floor, in groundwater, in plants, animals and even in humans