STUDIES ON IDENTITY OF MELOIDOGYNE SPECIES AND THEIR INTERACTIONS IN VEGETABLE CROP PATHOSYSTEM

DISSERTATION SUBMITTED TO THE ALIGARH MUSLIM UNIVERSITY, ALIGARH IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PHILOSOPHY IN BOTANY

SYED RAIS HAIDER

DEPARTMENT OF BOTANY ALIGARH MUSLIM UNIVERSITY ALIGARH (INDIA) 1987 J^^**" *^'l^l Ar,- Si.

' / . '-^ '*•* ^^ .^ 'S - . [•******«**************************1

I AFFECTIONATELY I DEDICATED TO MY PARENTS

**•**••*****•*****•******•*••••**•* Dr. M. WAJID KHAN Plant Pathology and Plant Ncmatolocy M.Sc. (Ban.), Ph.D. (Alig.), F.L.S., P.P.SI Laboratories READER Principal Investigator DEPARTMENT OF BOTANY CSIR Project—Airpollution-animate ALIGARH MUSLIM UNIVERSITY plant pathogen interactions ALlGARH-202 002, INDIA ICAR Project—Root-knot nematodes UGC Project "Cucuihit powdery mildews /).,./...i:^.;..lL-.!^.S7

CERTIFICATE

This is to certify that Mr, Syed Rais Haider

has prepared this dissertation as required for M.Phil,

(Botany) degree of the Aligarh Muslim University,

Aligarh, under my supervision and guidance. He is

allowed to submit zhis dissertation for evaluation

in partial fulfilcent of the requirements for the

degree of M.Phil, in Botanyo

( M, Wajid Khan ) Research Supervisor ACKNOWLEDGEMENTS

I would like to express my great gratitude to Dr. M.WaJid Khan, Principal Investigator of I.C.A.R., C.S.I.R. and U.G.C. Projects and Reader, Department of Botany, Aligarh Muslim University, Aligarh, my supervisor for suggesting the problem, encouragement, active guidance and keen interest in planning my studies for Ph.D. and preparation of M.Phil, dissertation.

A greatful acknowledgement is made to Prof.Khalid Mahmood, Chairman, Department of Botany, Aligarh Muslim University, Aligarh, for providing the facilities.

Financial assistance by the Indian Council of Agricultural Research, (ICAR), New Delhi, through Senior Research Fellowship sanctioned in the ICAR Project(No.1-21/ 84-PP) under the supervision of Dr. M.Wajid Khan is also gratefully acknowledged,

I am also thankful to Prof. J.N.Sasser, Chief Investigator of International Meloidogyne Project (IMP) and Crop Nematode Research and Control Project (CNRCP), Department of Plant Pathology, North Carolina State University, Raleigh, U.S.A. for sparing latest literature pertaining to my investigations. I am greatly thankful to Dr. S.S.Ashraf, Research Associate in the ICAR Project, Dr. M.Salahuddin (S.R.F.)» Mr. A.A.Khan, Mr. G.K.Sharma, Mr. M.R.Khan, Mr, S.K.Singh, Mr, Shahid Perwez and Mr. Mohdo Imran Khan, Research Scholars in Botany for their kind help and cooperation during the review of literature and preparation of dissertation,

I wish to extend my appreciation to my friends Mr, Mohd. Nafees, Mr. S.M.Mehdi, Mr. Aftab Husain, Mr. S.Zakir Husain, Mr. T.Shahid and Mr. Zaigham Hasan for their cooperation and understanding,

I am indebted to my parents and other family members for their encouragement, support and care throughout my educational growth and preparation of M.Phil, dissertation.

Finally, I beg to express my gratitude, thanks, appreciation and indebtedness to the "ALMIGHTY GOD" for providing and guiding all the channels to work in cohesion and coordination to make this study possibleo LIST OF CONTENTS Page

INTRODUCTION • • • 1

LITERATURE REVIEW • • • 9

(i) Distribution of Root-Knot Nematodes • • • 13

(ii) Identification of Root-Knot Nematodes • o • 36

(iii) Interaction between Plant Nematodes o • • 41

(a) Interaction between ectoparasites o • • 41 (b) Interaction between ectoparasites

and endoparasites 0 O • 43

(c) Interactions between endoparasites O 0 • 46 (d) Interaction between species of

Meloidogyne o • • 49

MATERIALS AND METHODS o • * 53

1. Survey and collection o c • 53 2. Identification of species and races of root-knot nematodes • • • 55

(a) Perineal pattern • • • 56

(b) Differential host test 0 • • 57 Maintenance of root-knot nematode

populations 0 0* 58

4o Pure culturing O 0 O 58

5c Preparation of inoculum • • o 58 6c Interspecific interactions of root-knot nematodes in coinhibitance 59

(a) Pot experiment 59 (b) Gnotobiotic system 60

111 Page

7. Histopathological studies 62 Growth performance 63 9o Intraspecific competition in root-knot nematodes 64 10. Pathotrophic ability 65

LITERATURE CITED 66

iv LIST OF TABLES Page

1o Species of Meloidogyne, .c 10

2o Countries of 8 geographical regions of the International Meloidogyne Project. <,.. 14

3. Species and races of Meloidogyne recorded in the IMP Region I (Mexico, Central America and Caribbean), oo. 18

4o Species and races of Meloidogyne recorded in the IMP Region II (South America), oo, 20

5. Species and races of Meloidogyne recorded in the IMP Region III (Brazil), .o. 22

6o Species and races of Meloidogyne recorded in the IMP Region IV (West Africa). ,o c 24

7o Species and races of Meloidogyne recorded in the IMP Region V (East Africa). oc. 26

8o Species of races of Meloidogyne recorded in the IMP Region VI (Asia), o,. 28

9o Species and races of Meloidogyne recorded in the IMP Region VII (Middle East). o.o 33

10o Species and races of Meloidogyne recorded in the IMP Region VIII (India). ,.. 37

11o North Carolina Differential Host Test Reaction Chart, «,. 42 INTRODUCTION

A crop pathosystem is comparable to an ecosystem, and. is defined on the basis of parasitism. The pathosystem concept includes analysis of pathosystem and its management and unites these aspects into one cohesive new approach (Robinson, 1976). Plant pathosystems are divided into two distinct kinds - natural pathosystem, and crop pathosystem - on the basis of their system control. The natural patho­ system which is also designated as wild plant pathosystem is autonomous. This autonomous control is primarily due to communication between basic components of the pathosystem - the host, the pathogen and the environment. The natural pathosystem is also often called as "disease triangle". An artificial or crop pathosystem has an additional component which is man and is consequently known as "disease square", Man influences the other three components profoundly. In crop pathosystem cultivars differ from wild hosts, cultivation differs from wild ecosystem and pathogen population can be artificially manipulated or managed (Robinson, 1976). In modern plant pathology the system approach has been introduced and it is purposeful in case of nematodes as well.

One of the major obstacles to the production of adequate supplies of food in developing countries is the damage caused by plant parasitic nematodes. Root-knot nematodes (Meloldogyne species), due to their world-wide distribution, exceedingly wide host range and interaction with fungi, bacteria, viruses resulting in increase in disease severity, are one of the major plant pathogens affecting the worlds food production. Meloldogyne species attack an array of economically important plants affecting both quantitatively and qualitatively. Vegetables, cereals, pulses, oilseed crops, fiber-yielding crops, fruit trees, plantation crops, ornamentals etc. are affected by root-knot nematodes on world­ wide basis. Estimated crop losses due to Meloldogyne species in major geographical regions of the tropics vary from 5 to 43% (Sasser, 1979). This, however, varies depending upon the crop, the species and the geographical region. In areas where management practices for root-knot nematodes are not practi- cised, average crop yield losses are estimated to be about 25% with damage in individual fields ranging as high as 60% (Sasser, 1980; Sasser and Carter, 1982).

Because of their enormous importance in agriculture throughout the world, the North Carolina State University at Raleigh (U.S.A.) initiated a world wide project known as International Meloldogyne Project (IMP) in July, 1975, to investigate various aspects of the problem in its totality. It was . funded by the United States Agency for International Development (USAID). Nearly 100 nematologists from 70 countries of the world cooperated with this project. The project terminated in 1984 after 9 years of functioning. It achieved its objectives of identifying the nature of problems and species and races of Meloidogyne existing in different regions of the world. Four species of root-knot nemato-les viz. Meloidogyne incognita, M, .javanica, M. arenaria anci M, hapla were recognized as major species. This project (IMP) was succeeded by a new one called Crop Nematode Research and Control Project (CNRCP) in 1984 to maintain its continuityo One of the main objectives of the CNRCP was to look for the suitable and effective measures to solve tne problems of root-knot nematodes identified by the IMP on various crops in different parts of the world. This project too has terminated in September, 1987 after 3 years of functioning.

At IMP headquarters at Raleigh (U.S.A.), samples of plant roots infected with Meloidogyne species obtained from 100 cooperators representing more than 70 developing nations were identified by employing different techniques. Of all the 91A samples studied, frequency of species encountered was as follows: M. incognita 52%, M. javanica 31%, M. hapla 8%, M. arenaria 7%, M, exigua 1% and others, such as M. gracinis, M. megatyla, M. microtyla, M. naasi, M. graminicola and M. oryzae 1%o Four races were differentiated in M, incognita by using the North Carolina Host Differential Test. Race 1 comprised 72% of 472 populations of M. incognita studied; Race 2, 13%; Race 3, 13% and Race 4, 2%, Similarly within the species of M. arenaria two races have been identified and designated as Race 1 and Race 2 (Sasser, 1982). Root-knot nematodes like many other countries are economically important in India as well. Ten species of Meloidogyne have been reported attacking large number of host plants (Sitaramaiah, 1984). Out of the ten species reported, only three, M. incognita, M. javanica and M, graminicola are predominant in India, M, incognita and in* .lavanica had been found to attack mostly vegetables, whereas M, graminicola is confined to rice (Krishnappa,1985). This picture of their occurrence and dominance has emerged from a relatively few studies. Similarly the reports on the estimation c»f yield losses are infrequent and vague, although Meloidogyne species has been reported to cause as high as 90% loss in case of okra (Krishnappa, 1985), Similarly, there have been very limited studies to differentiate the races in M. incognita. Three races of M. incognita has been identified based on differential host reaction in Karnataka and Tamil Nadu (Krishnappa, 1982). Race 1 was most prevalent. Race 2 was present only at Hebbal on okra and Race 3 at Mysore, Krishnappa and Setty (1983) in a later report indicated the existence of Race 1 and Race 3 of M, incognita in Karnataka. Routray and Das (1982) recorded Race 1 and Race 2 of M. incognita in and around Bhubaneshwar in Orissa. Race 1 of M. incognita has been recorded to exist in Haryana (Raja and Gill, 1982). Gill and Singh (1986) recorded the occurrence of Race 1, Race 3 and Race 4 in 12 different samples collected from different locations in the country. A perusal of literature on root-knot nematodes emanat­ ing from Aligarh gives an impression that M, incognita is the only species causing the disease on crops in and around Aligarh as well as the areas covered since the establishment of an active centre of research in Plant Nematology in 1952. Seemingly, no attempt was made to ascertain the identity of species of Meloidogyne existing in and around Aligarh on vegetables in cultivated fields. Because of observation of M. incognita in preliminary studies on certain crops in this area, it apparently became a traditional causal organism in subsequent studies on root-knot problems. Recent studies of Khan et_ al. (1984), Khan and Khan (1985) and Haider and Khan (1986) have recognized the existence of M. incognita, M, javanica and M. arenaria in Aligarh area. Khan £t al, (1984) found the occurrence of all the three species on vegetables in and around Aligarh. Similar results were obtained by Khan and Khan (1985) while studying root-knot infestation of weeds in vegetable fields. Haider and Khan (1986) also recognized the existence of these three species on ornamentals growing in and around Aligarh,

The responses of host cultivars to different species of Meloidogyne and their races are variable. It is, therefore, imperative to know the existence of different species of Meloidogyne and their races in a given area. Identity of Meloidogyne species and races, their pattern of distribution and relative dominance in different parts of the country have not been thoroughly investigated and well documented. These studies are of fundamental importance for successful cultiva­ tion of various crops. No attempt has been made for such studies in North India, particularly in the Indo-Gangetic plains of Uttar Pradesh. Such information is also not available from many other states of India, Similarly, responses of host cultivars to different races of M.incognita and M, arenaria have not been ascertained and it should receive sufficient study if the races of these species are established to exist in the country by future studies.

Coinhabitation in plant nematodes is apparently common in crop fields and crop pathosystems and as a result they influence each other under such conditions. There have been several attempts to study the interaction between different species of plant nematodes differing in their mode of para­ sitism (Norton, 1978; Khan, 1981; Khan, 1984; Eisenback, 1985; Khan and Khan, 1987). In some cases the population of inter­ acting nematodes is increased or decreased. Norton (1978) stated that our knowledge of competitive interaction which has been comparatively studied very little in nematology is not on as sound as an ecological basis as it is with other organisms. He contemplated that Cause's principle should be applied for interacting nematode populations as well. Cause's principle (Cause, 1934) or the principle of competitive exclusion states that only one species eventually occupy the niche. In other worlds, if two species occupy it, one eventually will outcompete the other even though each species by itself can function in that niche. Norton (1978) concluded that competition between species of nematodes exists and it is possible that some nematodes species are not able to survive in a particular habitat due to in part their inability to compete with other species. Before we arrive at this conclu­ sion for plant nematodes, comprehensive study in addition to what has already been done are required.

Some studies have been done on interactions between two sedentary endoparasites belonging to different genera, but studies on interaction between species of root-knot nematodes are scarce (Chapman, 1965; Johnson and Nusbaum, 1970; Kinloch and Allen, 1972), Since the establishment of races in some species of Meloidogyne there is no published record on inter­ action of races of M. incognita or M. arenaria with other species of Meloidogyne on crop plants. Thus, synergistic or antagonistic relationships that may develop between different species of Meloidogyne and races in a common pathosystem need to be investigated. When such studies have been completed, competitive pathotrophic ability and relative dominance of different species and races of Meloidogyne in common pathosystems of various crops and their cultivars will be known. Self- interaction or intra-specific interaction are also common in plant nematodes due to competition between the individual of the same species (Jatala and Jensen,1976)» On this basis, the trend in population build up and extent of crop losses 8

can be envisaged. In view of the foregoing, it is envisaged to include the following three major aspects in the proposed plan of work for Ph.D.:

1. Distribution and concentration of root-knot nematodes (Meloidogyne species) and their races on vegetable crops in Western Uttar Pradesh;

2o Identity of species and races of root-knot nematodes infecting vegetable crops in Western Uttar Pradesh; and

3. Inter-specific and intraspecific interactions of root- knot nematodes in co-inhabitance. LITERATURE REVIEW

Root-knot nematodes (Meloidogyne species) are cosmopoli­ tan in distribution and are an important group of plant namatodes infecting a wide range of economically important plants (Sasser, 1977)o Although root-knot nematodes cause recognizable galls on host roots, they remained undiscovered until the 19th century due to their minute size and protective habitat. They were first recognized by Berkeley (1855) on glasshouse cucumbers in England, Since then the pathogens were designated with different names for a considerably long period of time (Sasser and Carter, 1982), Root-knot nematodes were first named in 1879 by Cornu as Anguillula marioni in France (Cornu, 1879)o In 1884, Muller called them Heterodera radicicola. Thus, in the early 20th century, the name Heterodera radicicola (Greeff 1872), Muller 1884 was used for the root-knot nematodes. In 1924, Cobb observed that there were morphological difference between root-knot nematodes and cyst-forming Heterodera species and erected the genus Caconema to include H, radicicola (Cobb, 1924), In 1932, Goodey designated it as Heterodera marioni (Cornu 1879) Goodey 1932 (Goodey, 1932).

The present day name Meloidogyne was given by Goeldi (1887)c Chitwood (1949)» on the basis of morphological differences, particularly in the cuticular markings of the perineal region of adult females, described four species viz, Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949; 10

M. javanica (Treub, 1885) Chitwood,1949; M. arenarla (Neal,1889) Chitwood, 19^9; M. hapla Chitwood, 19^9 and one sub-species. He gave a generic diagnosis for Meloidogyne and differentiated it from Heterodera Schmidt,1871. Whitehead (1968) in a comprehensive review re-defined the genus and confirmed the morphological distinctness of 23 species of Meloidogyne. Franklin (1971) discussed the Meloidogyninae in relation to other Heteroderidae and summarized the most useful characters for identification of Meloidogyne species. Franklin (1972) in her review included 32 species and critically examined the most recent developments of the systematic of Meloidogyne with emphasis on the distinguishing characters of the various life stages. Upto 1976, 36 species were described from different hosts from various parts of the world (Taylor and Sasser, 1978). Franklin (1979) listed 36 valid species of Meloidogyne and summarized the historical background of the genus and the methods of identification based on females, juveniles and males. By June 1984, 54 species and two sub­ species have been described in the genus (Hirschmann, 1985). Since then, two more species have been added to the list (Table 1). Table 1, Species of Meloidogyne

1. Meloidogyne acronea Coetzee, 1956. 2. M. africana Whitehead, I960, 3. M. aquatilis Ebsary and Eveleigh, 1983. 4. M. ardenensis Santos, 1968. 5. M. arenaria (Neal, 1889) Chitwood, 1949. 11

6o M. artlellla Franklin, 1961).

7o M, bauruensis (Lordello, 1956) Esser, Perry, and

Taylor, 1976o

8, M. brevicauda Loos, 1953o

9o M. camelliae Golden, 1979. lOo M. carolinensls Fox, 1967 (rediscovered by Eisenback,1982),

11o M. chitwoodi Golden, O'Bannon, Santo and Finley, 1980o

12. M. coffeicola Lordello and Zamith, I960.

13. M. cruciani Gracia-Martinez, 1982. l4o M. decalineata Whitehead, 1968,

15o M, deconincki Elmiligy, 19680

160 M, elegans da Ponte, 1977.

17. M. enterolobii Yang and Eisenback, 1983.

18. M. ethiopica Whitehead, 19680

19o M. exigua Goeldi, 1887«

20o M. grahami Golden and Slana, 1978o

21. M. graminicola Golden and Birchfield, 1965o 22. M. graminis (Sledge and Golden, 1964) Whitehead, 1968.

23. M. hapla Chitwood, 1949o

24. M. incognita (Kofoid and White, 1919) Chitwood,1949.

25. M. incognita acrita Chitwood, 1949.

260 M, incognita wartellei Golden and Birchfield, 1978o

27o M. indica Whitehead, I9680

28o M« inornata Lordello, 1956,

29. M. .iavanica (Treub, 1885) Chitwood, 1949.

30. M. kikuyensis de Grisse, 196O,

31 o M. kir.lanovae Terentyeva, 1965. 12

32o M. kralli Jepson, 1983o 33. M. litoralis Elmiligy, 1968. 34. M. lordelloi da Ponte, 1969. 35. M. lucknowica Singh, 1969. 360 M. mall Itoh, Ohshima and Ichinohe, 1969. 37. M, megadora Whitehead, 1968, 38. M. megatyla Baldwin and Sasser,1979o 39o M. megriensis (Poghossian, 1971) Esser, Perry and Taylor, 197Fr 40, M. microcephalia Cliff and Hirschmann, 1984, 41, M. microtyla Mulvey, Townshend and Potter, 1975o 42, M. naasi Franklin, 1965. 43, M. nataliei Golden, Rose and Bird, 1981» 44, M, oryzae Maas, Sanders and Dede, 1978o 45, M. oteifae Elmiligy, 1968, 46, M. ottersoni (Thorne, 1969) Franklin, 1971. 47, M. ovalis Riffle, 1963. 48, M. platani Hirschmann, 1982, 49, M. poghossianae Kirjanova, 1963 = species inquirendo, 50, M. propora Spaull, 1977, 51, M. querciana Golden, 1979. 52, M. sewelli Mulvey and Anderson, 1980. 53o M, spartinae (Flau and Fassuliotis, 1965), Whitehead, 1968, 54. M. subarctica Bernard, 1981, 55. M. tadshlkistanica Kirjanova and Ivanova, 1965. 56. M. thamesi (Chitwood in Chitwood, Specht and Havis, 1962), Goodey, 1963.(Adopted from Hirschmann, 1985). 57« M. polygoni Golden and Handoo, 1984 (Golden and Handoo, 1984), 580 M. hispanica Hirschmann, 1986 (Hirschmann, 1986), 13

(i) Distribution of Root-Knot Nematodes

Sasser (1977) analysed the distribution of root-knot nematode species in different parts of the world. His report included existence of 11 species in Africa; 9 species in Central and South America; 18 species in the United States; 3 species in Canada; 11 species in Europe and the Mediterranean region; 10 species in India and Sri Lanka; 4 species in Russia; 5 species in Japan and 3 species in South-East Asia, Australia and Fiji Islands. So far ^36 species and two sub-species of root-knot nematodes have been described. However, about 99% of the populations identified through the efforts of the International Meloidogyne Project (IMP) headquartered at Raleigh,North Carolina, U.S.A. collected from the cultivated crops around the world were represented by only four species: Meloidogyne incognita, M. javanica, M, arenaria and M. hapla (Taylor ejb al., 1982). The first two species were found to be widely distributed in tropical, sub-tropical and warm temperate climates of the world, M. arenaria was also encountered in such climates but it was relatively less frequent. All three of these species occurred in areas with an average temperature of 36*0 or lower in the warmest month. M. hapla was found in temperate climates. It occurred in areas with an average temperature of 15"C during the coldest month, but was limited to areas with an average temperature of less than 27''C during the warmest month (Taylor et al. 1982). 14

As root-knot nematodes limit agricultural production to some degree in all countries, the International Meloidogyne Project enlisted the assistance of more than 100 nematologists associated with universities and research institutes in different countries particularly from the developing countries around the v/orld and grouped them into different geographical regions. Regional conferences were conducted periodically in each region to plan research objectives and approaches. About 76 countries grouped into 8 regions cooperated with the intprnational Meloidogyne Project (Table 2).

Table 2. Countries of 8 geographical regions of the International Meloidogyne Project.

Region I. Mexico, Central America and the Caribbean. Countries - Bermuda El-Salvador Costa Rica Panama * Guadeloupe Puerto Rico Jamaica Surinam Mexico Trinidad

Region II - South America Countries - Argentina Ecuador Bolivia Peru Chile Uruguay Colombia Venezuela Paraguay

Region III - Brazil Country - Brazil 15

Region IV - West Africa Countries - Benin Republic Ivory Coast Ghana Nigeria Senegambia Liberia

Region V - East Africa Countries - Botswana Tanzania Kenya Uganda Malawi Zimbabwe Seychelles Islands

Region VI - Asia Countries - Bangladesh Nepal Burma Pakistan Fiji Islands Philippines Indonesia Sri Lanka Japan Taiwan Korea Thailand Malaysia

Region VII - Middle East Countries - Cyprus Portugal Egypt Saudi Arabia Iran Spain Iraq Sudan Italy Syria Jordon Tunisia Libya Turkey Morocco Yemen Region VIII - India Country - India 16

Centres:- 1, Department of Botany, Aligarh Muslim University,Aligarh (Cooperators - Prof. S.K.Saxena and Dr. F.Wajid Khan) 2, University of Agricultural Sciences, Hebbal, Bangalore. (Cooperators - Dr. Kamma Krishnappa and Dr. K.G.H.Setty)

3, Bferyana Agricultural University, Hissar (Cooperator - Dr. D.S. Bhatti)

4o Department of Botany, University of Rajasthan, Jaipur. (Cooperator - Dr. P.C.Trivedi)

5. Mahatma Phule Krishi Vidyapeeth Agricultural Research Station, Vadner, Bhairo, Nasik (Cooperator- Dr. A.B.Pawar)

6. Central Rice Research Institute, Cuttack, Orissa (Cooperator - Dr. Y.S.Rao)

7. Department of Nematology, Rajasthan College of Agriculture, Udiapur (Cooperator- Prof. B.S.Yadav)

8. Division of Nematology, Indian Agricultural Research Institute, New Delhi (Cooperator - Dr. C.L.Sethi)

Project headquarter - Department of Plant Pathology, N.C.State University, Raleigh, U.S.A.

(Adopted from root-knot nematodes (Meloidogyne species) Affecting Economic Food Crops in Developing Nations by C.C.Carter and J.N. Sasser, 1982; and IMP Personnel Directory by J.N.Sasser, 1984. IMP Publication, Raleigh, N.C, U.S.A.)

The project was concluded in 1984 after functioning for 9 years. The pictures that have emerged from the studies under the aegis of IMP in different countries or regions of the world 17

with regards to number of speciet and races present in the country or region, their pattern of distribution, their relative dominance are presented in summarized forms herewith:

In the region I, Meloidogyne incognita, M. .lavanica, M. arenaria and M. hapla were recognized to be the most prevalent species. In addition to these four most common species, four more species viZo^M. exigua, M. kikuyensis, M. chitwoodi and M, oryzae were also found to be present in the region. Sosa-Moss (1985) summarized the occurrence of races of M_j_ incognita in this region. All the four races of M, incognita viz. Race 1, Race 2, Race 3» and Race 4 were detected to be present in the region. The distribution of races countrywise, however, varied. In Mexico Race 1 and Race 3; in El-Salvador Race 1, 2 and 3; in Costa Rica Race 1; in Panama Race 1 and 2; in Surinam, Race 1; in Trinidad and Tobago Race 1 and 2, in Guadeloupe Race 1; in Jamaica Race 1,2 and 3 and in Bermuda Race 1 were found to exist. Puerto Rico is the only country in the region where all the four races of M. incognita were recorded (Acosta and Negron, 1982; Ayala, 1976, 1981; Ayala et. aj. 1982; Taylor et ail. 1982; Burpee, 1981; Lopez, 1981; Tarte, 1981; Anais, 1981; Kermarrec, 1981; Hutton, 1981; Sosa-Moss, 1982; Oever, 1982; Singh, 1981 and Abergo, 1976) (Table 3),

In region II, Meloidogyne incognita, M, javanica, H* arenaria, M. hapla, M. exigua, M. decalineata and M. naasi 18

• « CO C\i en 00 CO o • CTi • en • o T— e 9 **> r~ T- r- C\l • • vO CO r— T- r\j CO vO CO CM T~ h- cr> 00 CO 00 •> C7> •^ r-- 'c; CT. CO CO cn T- o> en cr\ o r- « en c V- en CTv V- ^— ^— T- 0) (0 V- CO T— V— 0) •« t. •s o •<« •t Q) •« ^ •- u n S! •> CO d •« •> o d) N c 01 o (0 C 0) :3 o >iO 0) •H XI i ^ EH < i^ ti, CO < <: '^ 8 CO <: (U •H

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CO •H u CO CO CO CO CO H C H N H P. (U a U CO 5H cOi u CO CO X3 o C x: 0) • !U 2:1 21 21 SI CO w • CO CO CO CO CO CO CO 0) s 0 0 0 0 •H H 0 •H •H iH •H •H !-i u •H O •^ a a c c; CO m c 0) CO ra CO CO CO a C CU +J > > > > cu 0) > w •H CO CO CO CO i^H J-i CO G •n ni •n. •r^ CO CO •nj 0) M 0 • 0 ^1 21 21 SI 21 21 C o •H •k CO CO CO CO CO CO CO CD CO •H CU +^ -P P" -P +^ •P -P •P 4-> o fl •H •H •H •H •H •H •H •<—I •H M >, C C C c c C tiC bC bi bJ[ bC bC bC s bt 0 0 0 0 0 0 0 0 0 0 XJ 0 0 0 0 0 0 0 0 0 •H C C C C C c; G C 0 •H •H •H •H •rH •aH •H •H •H H 0) • • • • • • *i-« 2 2 2 2 2 SI

0 CO CU 0 0 0 •H -d •H 3 XS CO CO od 0 CO s CO > n CO rH 0 0 0 CO -rt rH •P p CO E CD •H 0 4^ S^ •H CO c e -p CO XJ CO •H U •H c CO fn CO C CO E ?< 0 SH •H 1 O QJ 0 CO D CO 0 :3 3 S-. rH O m 0 Du C5 •-0 s CL, C/1 EH W 19 were found to be present (Cabanillas, 1985). In Chile, M. incognita, M, .lavanica, M. arenaria, M, hapla and M. naasi were most pre-dominant. Race 2 of M. incopjnita and Race 2 of M, arenaria have been identified to be present in the country (Gonzalez, 1982). Navarro (1982) reported the occurrence of I2» incognita, M. .iavanica, M« hapla and M. exigua from Colombia, He also recognized the Race 1, Race 2 and Race 4 of M. incognita from economically important crops. In Peru, Guerra (1982) reported the existence of M, incognita. M. javanica, M. arenaria and M. hapla, the first two being of major occurrence, Costilla (1982) from Argentina reported about the distribution of root- knot nematodes in different ecological areas especially those of the north-eastern part of the country. He found M.gavania, M. incognita and M. arenaria present in the area, M, .iavanica was predominant. Mixture of the two of the three species in the same area and even in the same plant were also found, M» hapla and M, decalineata were detected only once in minor infestations of potato and on bean. Race 1 and Race 2 of M. incognita were identified to exist in the country. In M, incognita Race 1 in Venezuela, Race 1 and Race 3 in Uruguay, Race 4 in Ecuador and in M, arenaria Race 2 in Bolivia and Uruguay have been identified (Taylor _et al, 1982) (Table 4),

In Brazil (Region III), 12 species of root-knot nematodes were recorded by M. incognita and M. javanica were recognized as most widespread and important ( Ferraz, 1985). Boock (1951) reported the occurrence of M, Inco^.nita on potato 20 CM CM C\J CM 00 CO 00 O) CJ\

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tubers, M. javanica, _M. hapla,anct M, arenaria were first iden­ tified by Carvalho (195A) on soybean roots. Lordello (1956) described M. inornata from soybean var, Abura. Lordello and Zamith (1958) found M. exigua attacking coffee plants in the state of Sao Paulo, Lordello and Zamith (1960) described M. coffeicola, a new species that was causing the death of coffee plants in the state of Parana. M. thamesi was found parasitizing Artocarpus incisa L, in Pernamuco. A new species £1, lordelloi was reported by Ponte (1969) as parasite of a cactus, Cereus macrogonus, in the state of Ceara and another new species M. elegans in 1977 (Ponte, 1977). All the four races of M. incognita and Race 2 of M. arenaria are known to exist in the country (Table 5).

In the region IV, only six countries were actively involved in the International Meloidogyne Project, Only three species of root-knot nematodes, M. incognita, M. .javanica and M, arenaria in the order of abundance were recorded in Nigeria (Ogunfowora, 1981), M. incognita was more prevalent in South Nigeria while M. javanica in Northern Nigera (Caveness, 1978; Ogbuji and Dierua, 1978; Ogunfowora, 1978). Race 1 and Race 2 of jM. incognita and Race 2 of M. arenaria have been identified to be present in the countryo Meloidogyne species was one of the most important parasites on upland rice in Nigeria as reported by Fortuner (1981), Hemeng (1981) found M. incognita occurring in Ghana and it accounted for about 79% of the country collec­ tions. It was found alone as well as in mixed population with 22

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M, javanlca in the forest zone and in the Greater Accra zone (Hemeng, 1981). All the four races of M, incognita were iden­ tified to be present in the country. Merney (1976) reported the occurrence of M, incognita, M, javanica, and M. arenaria in Ivory Coast, Race 1 and Race 2 of M. incognita and Race 2 of M. arenaria are known to exist in the country (Fortuner,1981), Nieuwenhuyzen (1976) found M, incognita (Race 2) and M..1avanica in Liberia (Table 6).

Saka (1985) summarized the occurrence of Meloidogyne species in East Africa (Region V). Thomas and Taylor (1968) reported that in Eastern and Central Uganda M. incognita and M, incognita acrita were almost equally common. However, Bafokuzara (1981) reported that M. javanica was the commonest species in Uganda. M, javanica was also common in Zimbabwe (Way, 1981). M. incognita acrita, M. arenaria and M, hapla were also reported to exist in the country (Martin, 1957). Out of all the species recorded,M. .javanica emerged as most common. Of the two races of M. incognita differentiated in the -country. Race 3 was more prevalent than Race 1. M. hapla was also present in the Vumba area of the Eastern highlands as well as Invanga, Zimbabwe (Richardson, 1978). In Central, Western and Southern Tanzania, M. .javanica and M. incognita were recognized as wide-spread species but M. javanica was most predominant (Whitehead, 1969). Swai (1981) summarized that seven species of Meloidogyne viz., M. .javanica, M» incognita, M« hapla, M. ethiopica, M. decallneata, M. africana and M, kikuyensis 24

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occur in Tanzaniao Out of these seven, the first three species were most economically important. In Malawi M. .iavanica and M. incop;nita were recognized as widely distributed species (Saka, 1981) (Table 7).

In Asia (Region VI), many countries have done considerable studies on survey and identification of Meloidogyne species and have found that the distribution of M. incognita, M. javanica, M. arenaria and M. hapla is quite extensive in the region (Davide, 1985). Earlier, Madamba (1976) had stated that only a few surveys have been conducted to determine which species of Meloidogyne were present in South East Asia. All the four major species appeared to be present in South East Asia with the dominance of M. incognita. The extensive survey carried out in all agro-ecological zones of Sri Lanka have revealed that in the country there were five species of root-knot nematodes: M. incognita Race 1, M. javanica., M. arenaria, M. hapla, M. brevicauda (Sivapalan, 1981). Choi (1981) identified four species of Meloidogyne in Korea viz., M. arenaria, M. hapla, M. incognita and M. javanica. Occurrence of M. incognita Race 1, Race 2, and M. javanica was reported by Razak (1981) from Malaysia. Nishizawa (1981) detected the occurrence of M. incognita Race 1, M. javanica and M. hapla in Japan, Davide (1981) confirmed the findings of Valdez (1968) and Cortato and Davide (1968) who had observed the presence of M. incognita, M. javanica and M. arenaria in Philippines. 26 ON

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Six species of root-knot nematodes were found to be present in Thailand, M. incognita was dominant species as it was found on various economically important crops. M. javanica» M. arenaria were less prevalent. M, graminicola, M, exigua and M. naasi were also recorded but from specific areas. Race 1 and Race 2 of M, incognita are known to exist in the country (Sontirat, 1981). The species and races of root-knot nematodes that have been reported in Taiwan include M, incognita Race 1,2 and 3; M. javanica; M, hapla; M, arenaria and M. acrita (Cheng and Tu, 1980; Wang, 1978; Yang et al. 1977). M. incognita, however, is considered as most common species (Tsai, 1981).

All the four major species of root-knot nematodes were found in Pakistan associated with many different crops of economic importance. Race 1 of M. incognita have been identified to occur in the country (Maqbool and Saeed, 1981). M. .javanica was recognized as the dominant species causing significant damage to vegetables in Bangladesh and M, incognita Race 1, M, arenaria and M, graminicola was also reported to occur in the country (Choudhury, 1981), Hogger (1981) reported the occurrence of M, incognita and M, javanica from Nepal. M.incognita was most frequent root-knot nematode species followed by M. javanica and M. arenaria in Indonesia. Race 1 of M.incognita have been reported to occur in the country (Widjaja, 1981). M, javanica, M. incognita and M. graminicola were found to exist in Burma (Myint, 1981) (Table 8). 28

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Ibrahim (1985) summarized the occurrence of root-knot nematodes in Middle East (Region VII). Ibrahim ejt a_l. (1976), Oteifa (196^) and TarJan (196A) reported the occurrence of root-knot nematodes (Meloidogyne species) on many economically important plants grown in Northern Egypt. Ibrahim (1979) demonstrated that M. incognita, M, javanica and M, arenaria were present in Northern Egypt, Populations of M, incognita contained all the four races. Race 2, however, dominated. Race 1 of M. arenaria was a]so identifxed. In general, M. incognita population comprised 46%, M, javanica 3% and M. arenaria 24%, Elgindi and Moussa (1979) studied the occurrence and distribu­ tion of Meloidogyne species in Egypt, The pathogens were wide­ spread in many localities. Three species and one sub-species were identified as M. arenaria, M. arenaria thamesi, M.incognita and M. javanica. Abu Gharbieh (1979) reported the occurrence of M, javanica and M, incognita in Jordan,

Abivardi (1978) recognized the existence of M. javanica, M. incognita and M. hapla in 8 district of Fars Province in Iran. M. javanica was distributed in all districts whereas M. incognita was observed in Fosa, Kazerun, Neyriz and Shiraz. M, hapla was found only in Abadeh district. Race 2 of M, arenaria was identified to exist in the country (Abivardi et al, 1979). Stephan (1979) reported the occurrence of M, incognita, M, javanica and M, arenaria in Iraq. Five species of root-knot nematodes viz., M. javanica, M, incognita, M. arenaria, M. africqna and M. megadora were reported in Sudan 31

(Yassin and Zeidan, 1979). From Yemen, Sikora (1978) reported the occurrence of M. incognita Race 1 and 3 and M. javanica . Root-knot nematodes were serious pests of crops in Saudi Arabia, Race 1 and Race 2 of M. incognita have been identified in the country, Eissa et_ al. (1979) found M, incognita Race 2 as dominant root-knot nematode in the country. Agadr e_t a]_. (1979) reported the occurrence of M, .javanica, M. incognita Race A- and M, arenaria Race 2 in Morocco,

Khan and Dabaj (1980) reported the existence of M. javanica and M, incognita on vegetable crops grown in Tripoli region of Libya. Dabaj and Khan (1981) identified M, rjavanica and M. incognita as the species infecting tomatoes and potatoes in the Western region of Libya, M, javanica was found to be dominant. Race 1 and Race 2 were differentiated in M, incognit_a. In Italy five species viz., M, incognita, M, javanica, M, naasi, M, arenaria and M. hapla have been; found attacking cultivated plants (Di Vito, 1979; Lamberti, 1979)o The latter three species were less common and present in limited areas (Lamberti, 1979). Race 1 and Race 2 of M.incognita were recognized to exist in the country (Taylor and Sasser, 1978).

In Cyprus, M, javanica and M. incognita Race 2 were identi­ fied. M. javanica was predominant (Philis, 1979). Yuksel (1979) reported the occurrence of five species of root-knot nematodes viz., M, incognita, M. javanica. M. acrita, M. arenaria Race 2, M, hapla in Turkey, In Greece, M, javanica, M. incognita Race 1 and M. arenaria were collected throughout the coastal 32

region at elevation between 200 meters; M, hapla was found only in one location at an altitude above 450 meters (Pyrowolakis, 1975). M. incognita, M. javanica, M. arenarla, M. thamesi, M. acrita, M. artiella, K. exigua, and M. hapla are the species of root-knot nematodes occurring in Greece (Koliopanos, 1979). Santos and Abrantes (1979) indicated that in Portugal, H* incognita Race 3 and Race 4 and M. arenaria Race 1 and M. hapla were present.(Table 9 ).

A number of species of root-knot nematodes on a variety of crops are on record in India (Region VIII). Till 1977, eight species of root-knot nematodes viz., M, incognita M. javanica, M. hapla, M. indica, M. lucknowica, M. brevicauda, M. thamesi and M. graminicola were known to exist in the country (Sasser, 1977). Krishnappa (1985) while analysing the occurrence of root-knot nematodes in India stated that 10 species occur in the country, M. incognita is recognized as most dominant followed by M. .-javanica and M. graminicola. Swarup (1962) while reporting the prevalence of Meloidogyne species on vegetable crops in Delhi recognized M, incognita, M. incognita acrita and M, .lavanica as common species. Sethi _et al_. (1964) also reported the occurrence of N. .javanica and M. arenaria around Delhi. M. thamesi was recorded for the first time from India on Eragrostis pilosa (Sethi _et £l. 1964). Race 1 of M.incognita was identified by Gill and Singh (1986) from Delhi. 33 ... OA vD f- « S CO C^ CD a^ «t CTx CTiCTi •> • a\ w T— fn S- T- T- -H 0^ • T- W Ol CTi 3 o- • * D ... • • « I') V— •• •> C o> • d) * ..«o 00 r-ll • ••>CT\ W •r 3 C -H V- n o • rH|««> •-a^ S r^ nJl c^ CTitN cu •. CO m •' .. p> c a> a> s r^ a^ fo _C Q ,C 'd • c OJ IS *X) v£) O T^ ^ -t^l en CT\ •^ 0» a ;< -H "-•i o fn ON 0)1 V- ^~ '•:; •H a -'I m u 0) T- 0)1'^ T- CV «s ** r^ X) ''^ -W 01 !H x^ C-d 0) M B -• - e. ••-•• d T< c O -i-^ CO t, '.V r; ^^0)1 a: w •H 05 r -H 'd J-, ;^ ,•; +j ;. 'M r" CP CO •H x: Vi a' _c r: « tt' 0 '^^ •H 01 O • C5 •' D o u rH ro -H T-J CD -rH O^ > > a > .-^ rH(0 1 C CD C M3 -d •H In Q) !^ !-, tUt^ •H -r-i cu t4 ."-.[N -I Ct! X3 .D 03 CD x: Xi 4-' K ,0 ri 0> .O X- •p •H 03 iVi OA ,5 x: cc XI cn bi) U^ M O FH M U V- < < (0 n -1 H V- < t< n N:: V- < CO •H O CaD to (U QJ J-( C\J

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Nirula and Kun-tr (1964,1966) identified M. incognita and M. jfvanica infe-:ting various kinds of plants in Northern India. Swamy and Govindu (1966) and Krishnamurthy and Elias (1967, 1968) from Karnataka; Mathur e_t al. (1969), Handa et al. (1971) from Jaipur District in Rajasthan; Bharadwaj et_ al. (1972) in Solan area of Himachal Pradesh; Jayaraman et al.(1975) in Tamil Nadu; Raveendran and Nadakal (1975) in Kerala; Bhatti and Dahiya (1977) from Haryana; Sinha et al. (1977) in Bihar and Sen and Dasgupta (1975, 1977) in West Bengal reported the occurrence of M, incognita and M. javanica.

M. graminicola is reported to exist in Bangladesh and India on rice crops (Bridge and Page, 1982; Page and Bridge, 1979; Rao, 1978). In India, the nematode is known to infect rice in Assam, Orissa, Tripura and West Bengal and areas of its concentrations have been identified (Pal and Jayaprakash, 1983; Rao et _al. 1971; Roy, 1973). M. incognita was found in Itanagar, Arunachal Pradesh (Mishra and Jayaprakash, 1980). Recently, Soni and Nama (1982) observed the presence of M. incognita and M. javanica in Jodhpur district of Rajasthan.

Routray and Das (1982) found the occurrence of two races of M. incognita in and around Bhubaneswar, Orissa. Krishnappa (1982) and Krishnappa and Setty (1983) found the existence of M. incognita (Race 1, Race 3) in Karnataka. Race 1 and Race 4 of M. incognita have been recorded from Haryana (Raja and Gill, 1982; Gill and Singh, 1986). The distribution of root-knot nematodes was reportei by Verma and Singh (1983) in Garhwal hills. 36

Gill and Singh (1986) reported the occurrence of Race 1, Race 3 and Race 4 from 12 different areas of the country (Table 10).

The number of sporadic and casual reports of the occurrence of species of root-knot nematodes associated, with different kinds of crops from one or the other area in the country are too many but systematic studies to determine the occurrence of various species in different states of India, their pattern of distribution and relative dominance and such studies with regard to races of some species of root-knot nematodes are apparently lacking. In view of the establishment of root-knot nematode problem as fore-most nematode problem of the world; dominance of M. incognita and M. javanica in most parts of the world; and existence of races in M. incognita and M. arenaria, it has become imperative to work out this problem in full details in different regions of the country in order to tackle this problem of agricultural crops effec­ tively,

(ii) Identification of Root-Knot Nematodes

Morphology of perineal pattern and differential host test are primarily used for identification of species of Meloidogyne. Differential host test also helps in differen­ tiating the races of M. incognita and M. arenaria. If this approach proves inconclusive, then further morphological. 37 >. CM in •^ -*-' t^ t^ •>x: • •H >1 -p • •« • ON a\ 1-1 bO v£) • x: CD CTv '-CXJ T~ T—, -r-i C GO 4-> rH D 4J •-CO KO T- CO •« •k • CD -H -H cr> ON • • CM >.o f/) T— C ;3 CO 00 T- •^ cr> ^ '-'1 rHJOO •H •« 0) ^ •H BV£) CT. C •s V~ •• 051 cDJCr. x: -ci -c •o ••> c o • *« (T> > CO 0^ •^ en • " iX V- CD C C C LPI U!1 c CM ••> V- O C V- +^l +'l Q CD CD CD O C • OJ "^^J- C5 -C - - cDHjro OJI 0)1 •> CTi-r) • a^\D •k to •> 0! CD cD^-: CD O CD 1-1 C r- CO « QJ T- cr^s: 'C:i -H CO D. C +M ''~j c n. S.1 ''"^r-l "<'i TJ •> c CO ^ -H OJ CD culd 5 H CD PC C^ 'O (-1 C e Pk • •H M C q U CD •o CD C •H C CD ft- o •H •-[!] x: s: . 3 CU C ' JH X: XJ vvs •. • a .'^ i:> gg " E V£) to to K^ -C -Xi -H U CO to P r^ CM VO a* CD t-i CO -d CO MD 'O -H -r-l CO p r. c m >.-H CD l>- GO Q-J > ncj f-'. ? -p c > a\ c SH j-f o^ CD CD O x: CD SH x: o%cric'> CD CD -rf , CO Q) CO CO r- CD 1^ :^ T- :^: u: to '-JU: ;il T- V- v- ct;-' c5

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cytological and biochemical studies are made (Carter and Sasser, 1982). These methods were used in different parts of the world as well as at headquarters of IMP for identifi­ cation of species and races.

Females of each of the four major Meloidogyne species have distinctive perineal pattern. It is an external, finger print-like series of markings in the vicinity of the anus and vulva. The markings are readily visible under a light micro­ scope. The characters of perineal patt&rns of four major species of Meloidogyne are as follows:

M. incognita; Perineal patterns of M. incognita have a distinct high dorsal arch composed of smooth to wavy striae. Some striae fork near the lateral lines but distinct lateral lines are absent. Often there are striae that bend towards the vulva. The high, squared-off dorsal arch is the main character for this species (Eisenback et al. 1981).

M, javanica : Patterns of M. javanica have rounded to flattened dorsal arch. Clear lateral lines are the important features of this pattern which completely divide the pattern into dorsal and ventral regions. No or few striae cross the lateral incisures and some striae bend toward the vulva (Eisenback et al. 1981).

M. arenaria : The dorsal arch in M. arenaria is flattend to rounded. The striae in the arch are slightly indented at the lateral lines and generally form a shoulder 40

on the arch. Sometime the dorsal and ventral striae meet at an angle at the lateral lines. Some striae are forked and are short and irregular near the lateral lines. The striae are smooth to wavy and some may bend toward the vulva. The patterns may also have striae that extend laterally to form one or two wings. Variants of some populations are similar to patterns of M, hapla or M. incognita (Eisenback ejb al., 1981),

12• hapla : Perineal pattern of M. hapla are nearly round hexagons to slightly ovals. The dorsal arch is generally flattened. Lateral lines are indistinct, although they may be indicated by slightly irregularties in the striae or by dorsal and ventral striae that meet at an angle. Some striae may extend laterally and form one or two wings. Striae are smooth to wavy. The tail terminal area is usually marked by puncta- tion which is a good character for this species, Punctation may be absent in some preserved specimens due to fixation pro­ cedures (Eisenback £t al, 1981).

In differential host test, six standard -host plants are inoculated. These are cotton cv, Deltapine 16, tobacco cv, NC 95, pepper cv, California Wonder, watermelon cv, Charleston Grey, p«anut cv. Florunner and tomato cv. Rutgers. Fifty days later the host roots are examined for developed galls and eggmasses. On the basis of host susceptibility (indicated by ^) or resistance (indicated by -), pure populations of four major species - M, incognita, M, javanica, M. arenaria and M, hapla 41

and races of M. Incognita and M. arenaria are distinguished (Table 11),

(lii) Interactions between Plant Nematodes

Plant parasitic nematodes occur in polyspecific commu­ nities and the most species have a wide host range with consider­ able overlap. Therefore, many opportunities exist for interactions between nematodes themselves (Oostenbrink, 1966), The interactions between the nematodes is usually negative and may be categorised as competition - resource use type (Khan, 1984), Competition is more severe between the species of similar feeding habits.

Interactions may occur between different genera or different species of the same genus. Further, such interactions may involve ectoparasite and endoparasite; ecto - and semi - endo parasites; semi-endo and endoparasites or genera or species with similar mode of parasitism. Some reviews on this aspect of nematology are those of Norton (1978), Khan (1981) Khan (1984), Eisenback (1985), Khan and Khan (1987). Interactions involving different plant parasitic nematodes are summarized below;

(a). Interaction between ectoparasltles;

The number of studies on interactions between ecto- parasitic species of plant nematodes are relatively a few, but these studies have demonstrated convincingly that ectoparasitic 42

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(b). Interactions between ectoparasites and endoparasites i

Studies on interactions between nematodes differing in their mode of parasitism are comparatively more. The interactive effects have been observed to be inhibitory either for all the interacting species or one of the species was harmed while the other remained unaffected. Chapman (1959) observed that in concomitant inoculations on red clover and alfalfa, population of Pratylenchus penetrans remained unchanged in the presence of Tylenchorhynchus martini. However, _T. martini population declined in the presence of P. penetrans. Johnson and Nusbaum (1968) reported that on five varieties of corn population of Trichodorus christiei was higher in the presence of Pratylenchus zeae but _T. christiei population was suppressed in combination with Tylenchorhynchus claytoni and T, claytoni was suppressed by T. christiei. Sikora _et _al. (1972) reported 44

inhibition of Meloidogyne naasi on bent grass in the presence of Tylenchorhynchus agri« However, T. agri and Pratylenchus penetrans were not affected by any of the combinations. Amosu and Taylor (1974) while studing interaction of P. penetrans and _T, agri and M. hapla on red clover observed that population of both P. penetrans and _T, agri increased geometrically when each was alone but arithmetically when each was in combination with M. hapla. Dominance of Hoplolaimus columbus on Meloidogyne incognita was demonstrated by Bird e_t al.(1974). Hasan and Alam (1975) reported inhibition of Hoplolaimus indicus in the presence of M. incognita on tomato. Miller and Mc Intyre (1975) demonstrated that on tobacco Tylenchorhynchus claytoni inhibits entry of P. penetrans. Van Gundy and Kirkpatrick (1975) observed that reproduction of Meloidogyne .javanica was inhibited when associated with Pratylenchus scribneri, Trichodorus christiei and Hemicycliophora arenaria on tomato. Reproduction of Scutellonema bradys was greatly inhibited in the presence of Pratylenchus coffeae on Guinea Yam (Acosta and Ayala, 1976). Pinochet _et al. (1976) reported that on grape-vine in concomi­ tant population Xiphinema index was reduced in the presence of Pratylenchus vulnus. Misra and Das (1977) noticed that Creconemoides ornatus, Hoplolaimus indicus and Tylenchorhynchus nudus in combination significantly affected the infectivity of Meloidogyne incognita in brinjal. Santo and Bolander (1977) reported that on concord grapes presence of Macroposthonia xenoplax tended to suppress Meloidogyne hapla reproduction. A5

Khan and Haq (1979) obtained mutual reduction in population of M. incognita and Tylenchorhynchus brassicae due to cohabitation on tomato. Schmidt and Stephen (1981) observed that on cotton Scutellonema brachyurum increased in the presence of Hoplolaimus columbus but were suppressed by M. incognita. Simultaneous inoculation of H, columbus either with M, incognita or _S. brachyurum resulted in an increase in its population. M. incognita population increased in combina­ tion with ^. brachyurum while E, columbus suppressed population of M, incognita. Kaul and Sethi (1982) observed decrease in M. incognita population in the presence of Heterodera zeae and _T. vulgaris on Zea mays. Donnell and Lewis (1984) observed that M. incognita was suppressed in the presence of Hoplolaimus columbus while M. incognita had no effect on H.oolumbus, Compe­ titive interactions between M. incognita, _R. reniformis and _T. brassicae were studies by Khan et_ ^, (1986a, 1986b) on tomato and eggplant. Mutual suppression in the rate of population increase was noticed when R, reniformis and T, brassicae or M, incognita and T, brassicae interacted on tomato (Khan e_t al. 1986a), In the combination of R. reniformis and _T. brassicae on eggplant, the multiplication of R. reniformis remained almost unaffected but multiplication of T, brassicae declined. In the combination of M, incognita and _T. brassicae on eggplant the multiplication of M, incognita was adversely affected. The rate of population increase of _T. brassicae also declined to some extent (Khan et al. 1986b). 46

(c). Interactions between endoparasltesi

Interactions between endoparasltes Involving migratory and sedentary species have been observed on a number of plants. Sedentary endoparaslte are highly specialized parasites and have a long lasting complex relationship with the host (Jones, 1981), Competition between two sedentary endoparasltlc species Is generally mutually suppressive because of the competition for available feeding sites and nutrition (Norton, 1969; Khan et al. 1986a, 1986b). Ross (1959, 1964) studied the Interaction of Meloldogyne incognita and Heterodera glycine on soybean and found that the population of M. incognita was suppressed in the presence of high population densities of JH, glycine. Inhibition of M, Incognita actira by the presence of Pratylenchus penetrans on tomato was shown by Estores and Chen (1970).

Johnson and Nusbaum (1970) studied the interaction between M. incognita, M. hapla and Pratylenchus brachyurus on four cultlvars of tobacco and found that the population of M, Incognita and M. hapla decreased in the presence of P. brachyurus. Turner and Chapman (1971) reported that simul­ taneous inoculation of Pratylenchus penetrans and Meloidogyne incognita had no effect on each other. However, prior Inoculation of P. penetrans significant3y reduced invasion by M. Incognita but the reciprocal treatment had no affect on the invasiveness of P. penetranso Chapman and Turner (1972), 47

however, observed reduction in penetration of M. incognita into red clover in the presence of high population level of P. penetrans. Further it was observed that P. penetrans laid fewer eggs in the presence of M, incognita. There was no discernible effect of P. penetrans on the development of M. incognita. Estores and Chen (1972) found that the population densities of P. penetrans and M. incognita were depressed when they coinhabited tomato roots, although P. penetrans was significantly inhibited by the presence of M, incognita. Jatala and Jensen (1976) studied the inter-relationships of Meloidogyne hapla and Heterodera schachtii populations on Beta vulgaris and found fewer galls due to M. hapla when _H^ schachtii was inoculated 10 days before M. hapla. On the other hand, cyst formation significantly increased when M, hapla was inoculated 10 days before _H. schachtii.

Gay and Bird (1973) studied the importance of host susceptibility in the study of concomitant nematode populations. On cotton Pratylenchus brachyuinjs greatly increased in the presence of M. incognita or M. arenaria. While on alfalfa and tobacco, no significant effect was observed. Chapman and Turner (1975) noticed decrease in the reproduction of Pratylenchus penetrans in red clover and alfalfa in the presence of M. incognita. O'Bannon et al^. (1976) observed that in mixed inoculation on citrus both populations of Radopholus similis and Pratylenchus coffeae were reduced. Gall development of M, hapla was suppressed when inoculations of _H. schachtii 48

preceded those of M. haplao An increase in cyst development was found when inoculation of M, hapla preceded H, schachtii. There was .no effect on populations of either M. hapla or H. schachtii when both were inoculated simultaneously. Sharma and Sethi (1976) reported that the infection and multiplication of M. incognita and Heterodera ca.jani were mutually inhibited by each other,

Kheir and Osman (1977) studied the interaction of Meloidogyne incognita and Rotylenchulus reniformis on tomato and found that the population of R. reniformis had adverse effect of M. incognita. Taha and Sultan (1977) noticed that the population of R. reniformis and Tylenchulus semipenetrans on grape seedlings did not have significant effect of each othero Taha and Kassab (1980) studied interaction between Meloidogyne .javanica, Rotylenchulus reniformis and Rhizobium species on cowpea and found that R, reniformis suppressed the population level of M. javanica when R. reniformis was inoculated prior to M. ."javanica. But the latter ultimately dominated because of high reproduction potential. Kaplan and Timmer (1982) found that Pratylenchus coffeae and Tylenchulus semipenetrans together tended to reduce the population size of each other on citrus. Jatala and Jensen (1983) observed that different stages of Meloidogyne hapla have different effects on Heterodera schachtii. Second, third and fourth larval stages reduced the growth and development of _H, schachtii. However, young females of M. hapla greatly enhanced the development of 49

H, schachtil and mature females of M, hapla greatly decreased the growth of jj, schachtii. Thomas and Clark (1981) reported that M. incognita and R. reniformLs inhibited each other population on sweet potatOo

Khan e_t aJ.. (1985) observed that in concomitant inocula­ tions of M. incognita and R. reniformis on tomato, the penetra­ tion and multiplication of R. reniformis were unaffected in the presence of low number of M. incognita. Increase in the inoculum level of M, incognita upto 100 juveniles affected multiplication of both species but penetration was unaffected until at very high inoculvim level. Multiplication of M. incognita was adversely affected by R. reniformis at high inoculum level, but penetration of M. incognita only declined when the initial population of both the nematodes were high. Khan e_t aJ. (1986b) observed that in concomitant inoculations of M. incognita and R. reniformis on eggplant, the multiplica­ tion rate of both species declined when compared with single species at the same level of inoculum. The reduction was more pronounced for M. incognita than R. reniformis. Similar results was obtained by Khan et al. (1986a) while working with tomato plants.

(d) Interaction between species of Meloidogyne

Meloidogyne incognita, M. javanica, M. arenaria and M. hapla are the major species constituting the large portion of the population in cultivated fields (Sasser, 1982). Mixed 50

infection on plants of infestation of crop fieia is common and natural, Meloidot.yne, an endoparasite, feeds on cortical region of the root. Since the feeding site is limited and the ecological niches of different species overlap, the two or more coexisting species interact and the one which dominates may- affect the population density of the other species. However, studies on interaction between the species of Meloidoeyne are very few.

Chapman (1965) studied interaction between M. incognita and M, hapla at various temperatures. At high temperatures M. incognita significantly dominated over M, hapla. In simul­ taneous inoculations of M. incognita and M. hapla at high temperatures, 90% of the females were of M. incognita and only 10% were M. hapla. Only 51% of the females were of H, incognita at low temperatures. Johnson and Nusbaum (1970) observed that on 'NO 95' and 'NO 2512' cultivars of tobacco, M. incognita suppressed M. hapla population. Besides, M. hapla reproduction was less in the presence of M. incognita, Kinloch and Allen (1972) reported that M. javanica predominated M. hapla in a mixed species infection on tomato at 20"C, Predominance increased with increasing mixed species inoculum levels. Invasion by M. hapla was more density dependent than M. .javanica.

It is apparant from the above review of literature that very little attention has given to investigate the possible interactions between species of Meloidogyne. M, javanica and 51

M. incognita are the two most common sp^^cies in cropical and subtropical regions of the world. They have more or less similar ecological requirements and thrive together in many different parts of the world. Some priJiminary studies (Khan £t al. 1984; Khan and Khan, 1985; Haider and Khan, 1986) indicate that M, javanica and M. incognita are most frequent species, found in mixed populations in and around Aligarh in Uttar Pradesh. Considering the climatic conditions of the area, it is expected that these species may have similar pattern of distribution in other districts of Western Uttar Pradesh, This, however, needs to be studied thoroughly before this pattern of distribution of the species in this area can be fully claimed.

Interaction of M, incognita and M, .javanica when present together in the same field infecting the same root system has not been studied. Whether their interaction in mixed population is inhibitory for each other or they develop synergistic relationship causing greater damage to the host or they remain neutra] without influencing each other is yet to be investigated and elucidated, V/hen they invade the same root system having same mode of parasitism and same feeding sites, receiving nutrition from the same host, some sort of influence over each other is envisaged with respect to development of host-parasite relationship and syncytia, fecundity, rate of population growth and resultant populations of the species. Whether the races of M. incognita behave differently in these respects or not is not knowno 52

Whether Cause's principle of exclusion of one species by the other operates and one spfcies can eventually be excluded from the community of these species or they develop a balanced relationship coexisting together in the crop fields, are some of the key questions that need to be answered by future researches. In the proposed study, it is planned to investigate some of these aspects so that some tangible answers can be found to these intriguing questions about possible interactions between species of Kieloidogyne especially M. incognita and M, javanica which are supposedly most common species in the Western Uttar Pradesh. MATERIALS AND METHODS

The different materials to be used and methods to be employed to investigate the proposed aspects are generalized as follows:

1o Survey and collection

Extensive surveys will be conducted in the areas of intensive vegetable cultivation in 17 districts of Western Uttar Pradesh namely; Agra, Aligarh, Almora, Bareilly, Bijnor, Budaun, Chamoli, Etah, Garhwal, Mathura, Moradabad, Pilibhit, Pithoragarh, Rampur, Shahjahanpur, Tehri-Garhwal and Uttar Kashi to assess the level of infestation of root-knot nematodes on vegetable crops and to understand the pattern of distribution of different species and races of root-knot nematodes in the region. The emphasis would be on following vegetable crops,

(i) Tomato (Lycopersicon esculentum Mill.) (ii) Eggplant (Solanum melongena L.) (iii) Cucumber (Cucumis sativus L.) (iv) Pepper (Capsicum annuum L.) (v) Okra (Abelmoschus esculentus (L.) Moen.)

Five to ten root samples of tlje vegetable crops will be collected at random from each field plots or other cultivation units in the locality under survey in polythene bags. Samples will be properly labelled and brought to the laboratory for 54 further examination. Root samples will be thoroughly washed and will be examined for the presence of galls. Number of galls per root system will be counted. Roots will be immersed in an aquous solution of Phloxin B (0.15 g/lit, tap water) for 15 minutes to stain the eggmasses. Number of eggmasses per root system will then also be counted. Gall index (GI) and eggmass index (EMI) will be rated according to the following scale:

0=0, 1 = 1-2, 2 = 3-10, 3 = 11-30, 4 = 31 - 100, 5. = More than 100 galls or eggmasses per root system (Taylor and Sasser, 1978),

From the data range and mean of GI and EMI will be determined for each crop in a locality.

To assess the incidence of the disease in different localities of the area, frequency of occurrence (percentage) of the disease in each locality on included crops will be calculated by the following formula: Niamber of cultivation units Frequency of occurrence {%) ^ with infection v ino Number of cultivation units surveyed 55

Similarly frequency of occurrence of disease on a particular crop in all the localities will be calculated as follows: Number of root samples FrequencT:. y of« occurrence (96/,v/\) = of a cro*p^ with infection x^ ^-.10^0 Number of root samples of the crop examined

Frequency of occurrence of disease and gall and eggm.ass indices will be used as criteria to understand the level of infestation of root-knot nematodes on different crops and in different areas. After identifications of species and races of root-knot nematodes,per cent occurrence of species and races on different crops and in different areas will also be computed,

2. Identification of species and races of root-knot nematodes

Characteristics of perineal patterns of females and responses of North Carolina host differentials (Eisenback et al. 1981; Taylor and Sasser, 1978) to different collections of root- knot nematodes will be used for identification of species and races. Samples collected during the survey will be processed for the identification of species and races of root-knot nematodes. At first instance, preliminary and tentative iden­ tification of the species from the field samples will be made by examining 10-20 perineal patterns of female from each root sample. After preliminary identification, the sample will be maintained on tomato in glasshouse. Each sample maintained in the glasshouse will be given an accession number from which 56

the detail informations about the samples recorded can be referred whenever required. When final identifications of the maintained populations of root-knot nematodes by employing perineal pattern characteristics and host differential tests are over, the results will be compared with the identification made directly from the field samples. In these studies, emphasis would be on following species of Meloidogyne.

(i) Meloidogyne incognita (ii) M. ^javanica (iii) M. arenaria (iv) M. hapla

The differential host test will also differentiate the known races of M, Incognita and M. arenaria (Taylor and Sasser, 1978), The identity of species of Meloidogyne and their occurrence in the area on various vegetables would thus be established,

(a). Perineal patterns

To identify the species of Meloidogyne maintained in glasshouse, mature females will be dissected out from large galls on the roots of tomato plants. Ten to twenty perineal patterns will be prepared from each population and will be examined microscopically to study their characteristics. The species will be identified on the basis of the characteristics of perineal patterns of each species as described by Eisenback et al. (1981). 57

(t)* Differential host teat

North Carolina differential host test (Taylor and Sasser, 1978) will be carried out to identify the species and races of Meloido^yne populations collected during the survey and maintained in the glasshouse. Seedlings of tomato cv. Rutgers, tobacco cv. NC 95, pepper cv. California Wonder, peanut cvo Florunner, water-melon cv. Charleston Grey and cotton cv. Deltapine 16 will be grown in clay pots with three replications. Two additional replicates of tomato will be included to determine the time of termination of the test.

After determining the number of freshly hatched second stage juveniles (Jp) per ml, plants will be inoculated with 5000 juveniles per pot. Juveniles will be added to a depre­ ssion made in the soil near the seedling 2 days after trans­ plantation. Inoculated plants will be kept at the glasshouse benches (27-30*0), Fifty to sixty days after inoculations roots will be harvested and thoroughly washed with tap water and examined for the presence of galls. Roots will then be stained with Phloxin B to facilitate the counting of eggmasses. Galls and eggmasses will be counted and GI and EMI will be rated on 0-5 scales of Taylor and Sasser as mentioned under the survey.

After rating the root system, results will be compared with the differential host test reaction chart (Table 11), This would distinguish the four species of Meloidogyne viz, M, incognita, M. .javanica, M. arenaria and M. hapla. The 58

identifications of species done on the basis of differential host tests will be compared with identifications made earlier by perineal pattern method for confirmation of their identity, of The race differentiation will be based on the results^ifferen- tial host tests and therecomparison with differential host test reaction chart (Taylor and Sasser, 1978),

3. Maintenance of root-knot nematode populations

Root-knot nematodes collected during the survey will be maintained on susceptible cultivars of tomato or other suitable hosts in a glasshouse by inoculating the seedlings grown in pots containing autoclaved soil with chopped infected roots or eggmasses collected from the infected root samples. The inocula will be further cultured in pure form,

4» Pure culturlng

Field populations of root-knot nematodes maintained in glasshouse, will be cultured in pure form by single eggmass inoculation. Single mature eggmass will be inoculated in pots around the roots of young tomato seedlings for each maintained collection separately, Sub-culturing will be done approximately every 2 to 3 months by inoculating new tomato plants with atleast 15 eggmasses, each obtained from the pure culture in order to maintain sufficient inoculum for further studies,

5. Preparation of inoculum

For differentiating the species and the races by differential host test and for other experiments, inoculations 59

will be made in the form of second stage juveniles (Jp). Second stage juveniles (Jp) will be obtained by incubating eggmasses in sterilized water in the incubator at 25*'C. After 72 hours, number of the hatched juveniles (Jp) will be collected in water suspension. Their number/ml will be standardized by counting the ten 1 ml. samples from the suspension and calculating the average,

6. Interspecific interactions of root-knot nematodes in coinhabltance

Preliminary studies have shown that M. incognita and M, javanica are common species in the area. Therefore, M. incognita and M. javanica will be selected to study their interspecific and intraspecific interactions in pots as well as gnotobiotic system in petridishes. A susceptible cultivar of tomato or eggplant will be selected as test plant for pot experiments and cabbage or cauliflower for gnotobiotic system.

(a)» Pot experiment

To study the interaction of M, javanica and M.incognita in pot conditions different combinations of various inoculum levels of M. incognita and M. javanica will be employed. Surface sterilized seeds of tomato will be raised in trays containing sterilized sandy loam soil. Split root system will be used during the experiments. In clay pots thick polythene sheets will be kept in order to divide the pots into two chambers and sterilized soil will be filled in both parts of 60

the pot so that the pots may have soil in two different chambers separated by the polythene sheet. Three-week-old seedlings of tomato will be taken out from trays and their root system will aseptically split into two halves before transplantation. At the time of transplantation one half of the root system will be placed in soil in one half of the pot and the other half of the root in the other half of the pot. One half of the root system will be inoculated with M. javanica and the other with M. incognita. Different combinations of varying number of second stage juveniles will be used for inoculations. The pots will be placed after inoculations on the glasshouse benches. After 50 days of inoculations, roots of plants from different treatments will be harvested and each half of the root from the pots will be treated with nitric acid (5%) or pectinase and the females will be released. Their number will then be counted in order to assess the effect of one over the other, if any.

(t>)» Gnotobiotlc system

For studying the interaction in gnotobiotic system surface sterilized seeds of cabbage or cauliflower will be grown in Dropkin and Boone nutrient medium (Dropkin and Boone, 1966). The seeds of test plant will be stirred in 1% streptomycin sulphate for 15 minutes and washed repeatedly in sterilized distilled water. Then seeds will be stirred in 0,2% mercuric chloride for 15 minutes and will be again repeatedly washed with sterilized distilled water. These 61

surface sterilized seeds will be placed on water agar (0,3%) and incubated for germination. After 2-3 days some seeds with emerging radicle will be transferred to fresh water agar plates and will be allowed to grow in an incubator. After 5-7 days, tops of the seedlings will be incised from hypocotyle regions and one seedling will be placed in each petriplate containing Dropkin and Boone medium. Roots will be gently pressed on surface of the medium. Then petriplates will be ino­ culated with different juvenile (Jp) densities of M. javanica and M« incognita (any race) in various combinations. Before inoculation, larvae will be surface sterilized with mercuric chloride (1,000 ppm)or hibitain(0,5%). The second stage juveniles (Jp) will be exposed for 2 to 3 minutes and then will be washed repeatedly with sterilized distilled water. All these operations will be done at the Laminar Flow bench under aseptic conditions and the petriplates will be incubated at 25"C (i1). Antibiotic and antifungal substances will be added to the culture medium to eliminate some problems of contamina­ tion.

After 50 days of incubation the roots will be collected from different combinations and will be treated with nitric acid (5%) or pectinase to macerate the root tissue, A gentle shaking of the roots on a glass plate manually will release the females developed in the root system. Their number will be counted. The females will be at randomly sampled and their perineal patterns will be prepared to identify the species. 62

Then the data so obtained will be computed to determine the ratio of the number of females of M, javanica and N.inco^nitae This would give an idea of dominance of one over the other, if any.

The morphometric studies of females will be undertaken to asses the interactive effect oil their development and growth, In morphometric of the females, following aspect will be taken into consideration:

(a Length of the body- (b Width of the body (c Length of the neck (d Width of the neck (e Length of the stylet (f Length of the median bulb (g Height of the median bulb

From the data the range and mean will be determined,

7. Histopathological studies

In order to study the influence of mixed infection of M. .javanica and different races of M, incognita on histo- pathology of root, experiments will be conducted by inoculating the plants with equal number of juveniles (1000 and 1000) of both the species in the root system. For comparison control inoculated with 1000 and 2000 juveniles of M. incognita and the other 1000 and 2000 juveniles of M. javanica will be kept. 63

Galled regions of roots from different treatments will be collected and fixed in F.A.A. for sectioning. Microtome sections (in series) of the galls from each treatments will be examined microscopically. Histopathological details of roots infected with M. incognita or M. javanica alone and of the roots infected with both the species will be studied and observations will be compared to assess the effect of their coinhabitance on histopathology. The following parameters will be used in this assessment,

(a) Number of giant cells around each female (b) Size of giant cells (c) ^fumber of nuclei in each giant cell

80 Growth performance

To study the impact of interactive effects on the growth performance of the plants^ experiments will be conducted in pots in greenhouse. Three-week-old seedlings of tomato or eggplant will be inoculated with different combinations of varying inoculum densities of M, javanica and various races of M. incognita. Pots inoculated with same number of juveniles of M, incognita alone and M, javanica alone will serve as control. The plant growth in terms of fresh weight and dry weight and root gall index and eggmass index determined after 50 days will be used as a criteria to evaluate their interactive effect on plant growth. 64

9. Intraspeclflc competition In root~knot nematodes

Intraspeclfic competition in Meloidogyne javanica and in different races of M» incognita will be scudied in pots. The effect of inoculum density (Pi) on their rate of population increase (RPI) will be studied by using 10, 100, 1000 and 10,000 J2 per plant . Then effect of the inoculation of the plants with same inoculum level in total but in instalments at different time intervals will be studied. The inoculation of roots for the second part of the study will be done as follows:

(a) Control (I) 10,000 Jp (in one instalment)

(b) 2,500 + 7,500 Jp (in two instalments, second instalment after one week)

(c) 5000 + 5000 J2 (in two instalments, second instalment after one week)

(d) 7,500 •»• 2,500 J2 (in two instalments, second instalment after one week)

(e) Control (II) (uninoculated)

Population of each species will be determined by isolating the females from the roots, as well as males and the larvae from the soil. Morphometries of the females will be studied and histopathology of the roots will be examined. The growth performance of the plants will also be determined. 65

10o Pathotrophic ability

To study the pathotrophic ability of M. .iavanica and M, incognita (all A races) on the same host,^-4-week-old seedlings of tomato cv. Pusa Ruby and eggplant cvo Pusa Kranti and Pusa Purple Long will be inoculated separately with freshly hatched 5000 Jp of all the four known races of M. incognita and M. javanica. Each treatment will be replicated five times. The uninoculated seedlings will serve as control. The experi­ ments will be terminated after 50 days of inoculations and following parameters will be recorded,

(a) Length of root and shoot

(b) Fresh and dry weight of root and shoot

(c) GI and EMI

(d) Final nematode population (soil and root population)

(e) Morphometries of mature females in all the five sets LITERATURE CITED

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