BP Singh

IIDetection Techniques for Plant Parasitic Nematodesin Imported Germplasm Material for ResearchArjun LalIntrol,iudionAmong the multicellular animals, nematodes are one of theoldest existing forms of life. Nematodes show considerablevariation in their habitat. They are found in all oceans, from thepolar region to the equator, from the literal zone to the abyssaldepths; they colonize freshwater lakes, riyers and marshes and alltypes of soil from the antarctic to the tropics; they parasitize inostgroups of animals (including other nematodes), and a wide varietyof algae, fungi, and higher plants. Of the total nematode species,about 25% are free-living (soil and fresh water), 10% are plantparasites, 15% are animal parasites and remaining 50% are marine.In agriculture, we are mainly concerned with those nematodeswhich attack crops and reduce yields directly or indirectly 'inassociation with other plant pathogens like fungi, bacteria andviruses.Nematodes attacking plantsA plant growing in soil is often attacked by one or morespecies of plant parasitic nematodes. Plant parasitic nematodes arefound in and about roots of host plant, or in the leaves, stems, buds,flowers and seeds of plantjs. There a~129.E:!.2.!~q9 ~p~cies of pl~ntpa~~s )).ematodes . attacking various species of plants. Theirgreatest diversity of form occurs, amongst parasites of roots. Agrain of galled wh~at lnight contain 30,000 nematodes. One gramof coconut root could yield about 400 Radopholus similis. By causing