NAVSARI AGRICULTURAL UNIVERSITY Theory Manual INTRODUCTORY PLANT NEMATOLOGY Course No. Pl. Path 2.2 (V Dean’s) nd 2 Semester B.Sc. (Hons.) Agri. PROF.R.R.PATEL, ASSISTANT PROFESSOR Dr.D.M.PATHAK, ASSOCIATE PROFESSOR Dr.R.R.WAGHUNDE, ASSISTANT PROFESSOR DEPARTMENT OF PLANT PATHOLOGY COLLEGE OF AGRICULTURE NAVSARI AGRICULTURAL UNIVERSITY BHARUCH 392012 1 GENERAL INTRODUCTION What are the nematodes? Nematodes are belongs to animal kingdom, they are triploblastic, unsegmented, bilateral symmetrical, pseudocoelomateandhaving well developed reproductive, nervous, excretoryand digestive system where as the circulatory and respiratory systems are absent but govern by the pseudocoelomic fluid. Plant Nematology: Nematology is a science deals with the study of morphology, taxonomy, classification, biology, symptomatology and management of {plant pathogenic} nematode (PPN). The word nematode is made up of two Greek words, Nema means thread like and eidos means form. The words Nematodes is derived from Greek words ‘Nema+oides’ meaning „Thread + form‟(thread like organism ) therefore, they also called threadworms. They are also known as roundworms because nematode body tubular is shape. The movement (serpentine) of nematodes like eel (marine fish), so also called them eelworm in U.K. and Nema in U.S.A. Roundworms by Zoologist Nematodes are a diverse group of organisms, which are found in many different environments. Approximately 50% of known nematode species are marine, 25% are free-living species found in soil or freshwater, 15% are parasites of animals, and 10% of known nematode species are parasites of plants (see figure at left). The study of nematodes has traditionally been viewed as three separate disciplines: (1) Helminthology dealing with the study of nematodes and other worms parasitic in vertebrates (mainly those of importance to human and veterinary medicine). (2) Marine nematology dealing with the study of marine nematode. 2 (3) Nematology dealing with the study of nematode parasites of plants and invertebrates and "free- living" nematodes (those living in soil or water and feeding on bacteria, fungi, decaying organic matter, other nematodes, microscopic invertebrates, etc.). Nematology is an important branch of biological science, which deals with a complex, diverse group of round worms known as Nematodes that occur worldwide in essentially all environments. Nematodes are also known as eelworms in Europe, nemas in the United States and round worms by zoologists. Many species are important parasites of plants and animals, whereas others are beneficial to agriculture and the environment. On the basis of nematode habitats and diversity, they can be grouped into 2 categories. Parasitic Free living Human : Ascaris, Enterobius, Wucheraria, Marine:Chaetostoma, Chromodora, Deontostoma Onchocerca, Ancylostoma, Dracunculus Other vertebrates : Trichuris, Dioctophyma, Freshwater and Soil Plectus,Dorylaimus, Mononchus Invertebrates : Mermis(Grasshoppers) Bacterial feeder soil nematodes: Romanomermisculicivorax(Mosquitoes ) Caenorhabditis elegans, C. briggsae EPNs (SteinernemaandHeterorhabditis) Plants: Anguina, Meloidogyne, Heterodera etc Panagrellusredivivus(biological indicators) General characteristics of the Plant Parasitic Nematodes • Nearly microscopic • Unsegmented Posses a stylet, Colourless • Wormlike in appearance (pseudoworm) • Highly developed pseudo-coelomates • Bilaterally symmetrical invertebrates; with a body cavity or vacuoles (pseudocoelom?) • Triptoblstic, tapering at both end, cylenderical • Only plant parasites (other than Protozoa) belonging to the animal kingdom • Obligate parasite • The basic difference between PPN and other are that the PPN have well developed Stylet for the penetration of the host and feeding sap of the plant. • Parasites of animals (humans, vertebrates, invertebrates) and plants. They Posses • Stylet or spear bearing • a complete digestive system (mouth, intestine, anus) • A tri-radiate pharynx • A circumpharyngeal nerve ring and a well developed nervous system • Four sets of longitudinal muscles separated by epidermal (hypodermal?) cords • One or two tubular gonads, which open through vulva in female and into the rectum in male Movement They are moved by Sinusoidal movements facilitated by contraction of the longitudinal muscles against the elastic cuticle made rigid by the high hydrostatic pressure of the body fluids - a hydrostatic skeleton . Significance • They can cause significant plant damage ranging from negligible injury to total destruction of plant material • Majority of these parasites feed on underground parts of plants 3 They lack • Specialized respiratory and circulatory systems are absent. Economic Importance of Plant Parasitic Nematodes Nematodes are ubiquitous, present in all moist to watery ecological niches in diverse situations like cold oceans, hot springs, mountain peaks, soil ecosystem, plants as well as animals. Phytoparasitic forms comprise about 10% of all the forms of nematodes that exist in various habitats and have different feeding behaviours. Phyto-nematodes parasitize all types of plants - from algae to plants and trees and damage to world food crops as well as tree crops, turf and ornamentals. There are about 6000 known species of phyto-parasitic nematodes belonging to 197 genera. Being obligate parasites, they must draw their nutrition from plant hosts and infect the plants. A handful of soil from around the roots of any plant would yield hundreds of plant parasitic nematodes belonging to at least 4-5 genera. One gram of coconut root may contain about 4000 eggs, juveniles and adults of burrowing nematode or about 5000 individuals of coconut ring nematode. Single acre of arable land contain 3 x 109 nematodes Marine beach sand contain 15 x 108 nematodes/acre Single wheat gall: Max. 1,00,000 nematodes Besides this direct damage, they also associate with bacteria, fungi and viruses to cause complex diseases. In the world 12.3 % yield losses was observed due to different nematodes, in developing countries it was 14.6 %, whereas in developed countries it was 8.8 %. The losses due to cereal cyst nematode cause Molya disease of wheat and barley was 32 million rupees in Rajasthan, Punjab, Hariyana and Himachal Pradesh, whereas 25 million rupees losses was reported only in Rajasthan state alone. Seed gall nematode, Anguina tritici(causing „Ear cockle of wheat when alone and „Tundu disease‟ when in combination with bacterium) was estimated to be Rs. 70 million in wheat only in North India. Pratylenchus coffeaein an area of about 1,000 ha in Karnataka was estimated to be Rs. 25 million is assessed in coffee due to. Beneficial nematodes In addition to the harmful plant parasitic forms, there are groups of nematodes which are beneficial as they parasitize the harmful insects and thus can be exploited as biological control agents against these pests.The entomopathogenic nematodes Steinernema and Heterorhabditisspp.and slug parasitic nematode Phasmarhabditis hermaphroditain a mutual 4 association with bacteria have proved to be successful biocontrol agents and are now being commercially produced in many countries. NO. CROP NEMATODE YIELD LOSS, % 1 Bidi Tobacco Root-knot nematodes.M. incognita&M. javanica 51.0,50.0 2 Brinjal Root-knot nematodes.M. incognita 26.2--50.0 3 Castor Reniform nematode, Rotylenchulusreniformis 33.0 4 Chickpea Root-knot nematodes,Meloidogyne spp. 84.0 5 Chilly Root-knot nematodes.M. incognita 28.0 6 Cotton Reniform nematode, Rotylenchulusreniformis 8.0-15.0 7 Cowpea Root-knot nematodes,Meloidogyne spp. 30.3-71.3 8 Fennel Root-knot nematodes,Meloidogyne javanica patho.-2 28.1 9 Ginger Root-knot nematodes,Meloidogyne spp. 51.2 10 Groundnut Root-knot nematodes,Meloidogyne javanica patho.-2 35.0, 59.4 11 Mung bean Root-knot nematodes, Meloidogyne spp. 7.5-65.0 Reniform nematode, Rotylenchulus reniformis 18.0-21.0 12 Mushroom Aphelenchoides spp 40.6-100 13 Pigeon pea Pigeon pea cyst nematode, (H.cajani) 46.0 Root-knot nematodes,Meloidogyne spp. 25-31 14 Rice Rice root nematode, (H. oryzae) 4.3-53.5 Rice cyst nematode, (H. oryzicola) 7.9-26.8 15 Sunflower Root-knot nematodes. M. incognita 38-84.0 16 Tomato Root-knot nematodes. M. incognita 28-47 17 Turmeric Root-knot nematodes. M. incognita 31.3 18 Wheat Root-knot nematodes. M. incognita 32.9 19 Citrus Root-knot nematodes, Meloidogyne spp. 14.2 20 Banana Root-knot nematodes, Meloidogyne spp. 19.2 5 Range of size • From <100 μm (Greeffiella minutum - marine) to >8 m (Placentonema gigatissima - parasite of the spermaceti whale). Fossil evidence • The fossil record of nematodes is at the least sparse. There are traces of what may be nematodes in Chinese Precambrian layers (>670 Myr), but few are older than 50 million years and none are old enough to give information regarding the origin of specific nematode groups. Types of nematodes on the basis of feeding habit and motility – Ectoparasitic nematodes • Migratory Ectoparasite • Sedentary Ectoparasite – Semi endoparasitic nematodes – Endoparasitic nematodes • Migratory Endoparasite • Sedentary Endoparasite 1. Ectoparasitic nematodes: These nematode live freely in the soil and move closely or on the root surface, feed intermittently on the epidermis and root hairs near the root tip. Generally does not pose much problem. Some ectoparasite transmit plant viruses dagger (Xiphinema spp.,), Needle (Longiderous spp.) and stunt nematode (Trichodorous and Paratrichodorous spp) A. Migraotory ectoparasite: These nematodes spend their entire life