ABSTRACT
Cultivation of Jatropha curcas L. for production of biodiesel as an alternative source of energy is crucial for sustainable development in Nigeria. Pests and pathogens especially fungi have been reported to be a major constraint to commercial cultivation of J. curcas in Asia and some West African countries. However, this is yet to be fully investigated and documented in Nigeria. Fungal pathogens infecting J. curcas in southwestern Nigeria were therefore investigated.
Two hundred plant samples were randomly collected from each of Ekiti, Lagos, Ogun, Ondo, Osun and Oyo states, Nigeria. Fungi were isolated from these samples and the isolates were identified using standard procedures. Pathogenicity tests of these organisms (n=12) were carried out on five J. curcas accessions (Ex-Basirika, Ex-Mbatdiya, Ex-Misau, Ex-Ibadan and Ex-Kano) in the screenhouse using Koch‘s postulates. The experiment was laid out in a Completely Randomized Design (CRD) with four replicates. The accessions were also grown for three years on the field in Randomized Complete Block Design (RCBD) layout with four replicates. Data were collected on occurrence of fungal organisms. Disease intensity (incidence and severity) were recorded at weekly intervals for 16 weeks after inoculation. Field evaluation of disease incidence (%) and severity (1-5, ranging from no disease to highly susceptible) was carried out at three months interval for three years. Data were analysed using descriptive statistics and ANOVA at a0.05.
Anthracnose, mildew, canker, dieback, fruit and root rots were common symptoms found on J. curcas in southwestern Nigeria. Colletotrichum gloeosporioides was the highest occurring fungal species in all the states with the highest occurrence (26.0 %) in Ekiti. Oidum jatrophae was the lowest with the least occurrence (7.1 %) in Lagos state. Colletotrichum gloeosporioides, Curvularia lunata, Fusarium oxysporum, Oidum jatrophae and Lasiodiplodia theobromae among the isolated fungi were pathogenic on Jatropha curcas in the screenhouse experiment. Reactions of the accessions to fungal diseases showed significant variations in disease incidence and severity. Susceptibility of accessions was in the order: Ex-Ibadan > Ex-Kano > Ex-Mbatdiya > Ex-Basirika > Ex- Misau (61.4 % > 59.5 % > 43.4 % > 37.4 % and > 28.3 %, respectively). Anthracnose was
the most prevalent disease encountered, with maximum incidence in the screenhouse (26.6
%) and on the field (95.7 %). Disease intensity for Colletotrichum leaf anthracnose, L. theobromae collar rots, Cankers, Oidum mildew, shoot dieback and F. oxysporum root rots was 59.7 %, 26.5 % , 16.4 %, 41.9 %, 43.1 % and 38.9 % respectively.
Five pathogenic and seven non-pathogenic fungi were isolated from Jatropha curcas in southwestern Nigeria. Colletotrichum gloeosporioides was the major isolated fungal pathogen and was the most virulent on Jatropha curcas. Ex-Misau was tolerant and it is therefore recommended for intensive cultivation.
| CONTENT | TABLE OF CONTENTS | PAGE |
| Title | i | |
| Abstract | ii | |
| Certification | iv | |
| Acknowledgements | v | |
| Dedication | vi | |
| Table of Contents | vii | |
| List of Tables | xiii | |
| List of Plates | xvi | |
| List of Figures | xviii | |
| 1.0 CHAPTER ONE: | INTRODUCTION | 1 |
| 2.0 CHAPTER TWO: | LITERATURE REVIEW | 5 |
- Origin and Current Distribution of Jatropha curcas L. 5
- Taxonomy and related species of J. curcas 7
- Propagation and cultivation of Jatropha 7
- Economic Benefits of J. curcas 9
- Medicinal uses of Jatropha 9
- Fertilizer production from seed of Jatropha 10
- Commercial raw material for soap and vanish manufacture from
Jatropha oil 11
- Pesticide uses of Jatropha oil 11
- Fuel production from Jatropha seed 12
- Land conservation and carbon sequestration 12
- Biodiesel production from seeds of Jatropha 13
- Importance of Plant Diseases 14
- Disease assessment 16
- Biotic constraints against J.curcas cultivation 16
- Fungi associated with seeds of J. curcas 18
- Fungal Diseases of J. curcas 19
- Foliar Diseases of J. curcas 19
- Passalora leaf spot 19
- Cercospora/Pseudocercospora leafspot 20
- Alternaria leaf spot 20
- Foliar necrosis/Anthracnose 20
- Powdery mildew on J. curcas 21
- Rust on J. curcas 23
- Vascular/root disease on J. curcas 23
- Foliar Diseases of J. curcas 19
3.0. CHAPTER THREE: MATERIALS AND METHODS 27
- Survey and Sampling Collection 27
- Experimental Site of the Study and Laboratory Protocols 27
- Sterilization of laboratory materials 27
- Potato Dextrose Agar preparation 28
- Culturing for identification of fungal flora associated with J.curcas. 28
- Laboratory isolation and fungi identification 29
- Source of Jatropha accessions used for seed health test and in
- Experimental Site of the Study and Laboratory Protocols 27
screenhouse and field studies 29
3.3.2. Pathogenicity test of fungal organisms isolated from J. curcas accessions 31
- Inoculation techniques used for pathogenicity screening of J. curcas
seedlings 31
- Re-isolations of fungal pathogens after inoculation 32
- Screening for Disease Resistance 33
- Disease assessment of different fungal pathogens in Screenhouse
- Screening for Disease Resistance 33
and natural field infections 34
- Development of screening methods and evaluation of resistance to
fungal diseases 34
- Determination of disease incidence and severity 35
- Disease assessment in the field under natural infection 36
- Disease progression on the field 37
- Anthracnose disease infection index (DII) 37
- Morphology of Colletotrichum gloeosporioides Spore 37
- Characterisation of Colletotrichum gloeosporioides (Penz.) Penz. et
Sacc causing symptoms of anthracnose on J. curcas 38
- Effects of planting season on disease incidence and severity 39
- Data analyses 39
- CHAPTER FOUR: RESULTS 40
- Diseased Samples Collected During Survey and Field Studies 40
- Fungal species isolated from Jatropha samples 40
- Percentage occurrences of fungal species isolated from Jatropha samples collected from the different states of S/W Nigeria. 43
- Percentage occurrence of seed-borne fungal pathogens associated 43
with five J. curcas accessions collected from the gene-bank of FRIN 43
- Disease symptoms observed in the field at Ibadan 43
- Disease Symptoms Observed in the Field 47
- Leaf spots 47
- Severe leaf blight and chlorosis 47
- Anthracnose disease on J. curcas leaves 51
- Petiole infection caused by C. gloeosporioides. 51
- Symptoms incited on Jatropha plants in later stages of development 51
- Twig necrosis 55
- Shoot canker on Jatropha curcas accessions 55
- Powdery mildew caused by Oidum jatrophae 62
- Fruit and seed infection 62
- Dry Rot on Jatropha Caused by Fusarium sp. 65
- Conidia of Curvularia lunata Isolated from Leaf Spot on J. curcas. 65
- C. gloeosporioides from infected Jatropha plants 70
- Pestalotia isolated from leaf spot symptom on Jatropha 70
- Fungal contaminants (a) (Cladosporium sp.) and (b) Rhizopus sp.
- Disease Symptoms Observed in the Field 47
isolated from J. curcas. 70
- Conidia of F. oxysporum isolated from infected parts of J.curcas. 76
- Lasiodiplodia theobromae 76
- Pathogenicity test of the fungal organisms earlier isolated from
Jatropha plants 76
- Reaction ofselected Jatropha accessions to canker causing pathogen 80
under different inoculation techniques
- Effect of inoculation of different pathogens on leaf spot expression 80
on J. curcas
- Effect of inoculation of different pathogens on leaf spot expression on
- Susceptibility scoring on Jatropha accessions after artificial inoculation 84
- Major disease symptoms observed on leaves at four to 12 weeks after inoculation 84
- Root infection caused by F. oxysporum 84
- Lesion development on stems caused by Colletotrichum sp. inoculation 88
- Disease reaction on Jatropha accessions after L. theobromae treatment 88
- Disease expression on Ex-Misau inoculated with Colletotrichum and
Curvularia species. 88
- Root infection caused by F. oxysporum 88
- Plant Weights of Inoculated Jatropha Accessions with their
Control Counterparts 92
- Anthracnose expression on J. curcas under natural infection
- Performance of five J. curcas accessions in the field under natural
infection by C. gloeosporioides 92
- Foliar infections in early and later stages of plant growth of
Jatropha accessions 96
- Expression of shoot dieback symptoms on seedlings of J. curcas at
six and 12 months under natural field infection 96
- Severity scoring of powdery mildew on Jatropha accessions under
field infection 100
- Screening of Jatropha under three seasons of field observation for
powdery mildew infection 100
- Root rot expression on J.curcas plants in the field
- Incidence and severity of shoot/tip dieback symptoms. 104
- Performance J. curcas Seedlings to Anthracnose Caused by
C. gloeosporioides in Two Field Locations at Ibadan South-West Nigeria 104
- Inoculum potential of C. gloeosporioides from Jatropha seeds in the field 104
- Performance of seedlings raised from three months stored J. curcas seeds 108
- Shape and growth rate of different Colletotrichum sp. isolated
from J. curcas 108
- Correlation analysis between incidence and severity of foliar
anthracnose on J.curcas. 108
- Leaf spot expression on J. curcas accessions during dry season
planting trial (2010) 112
- Leaf spot incidence and severity in the wet season (May – June 2011) 112
- Leaf spot expression during the dry season (Nov. Dec. 2011) 112
- Leaf blight expression on Jatropha seedlings at different planting seasons 116
- Comparison of differences between wet and dry season blight
severities in four Jatropha accessions 116
5.0. CHAPTER FIVE: DISCUSSION 119
6.0. CHAPTER SIX: SUMMARY AND CONCLUSION 137
LIST OF TABLES
TABLES PAGE
- Fungal species isolated from J.curcas in South-Western Nigeria 42
- Occurrence of fungal sp. on J. curcas from six states of Southwestern Nigeria 44
- Incidence of seed-borne fungal organisms associated with five
J. curcas accessions 45
- Incidence of canker on shoots of J. curcas accessions under natural infection 9 months after planting (MAP) in two locations 61
- Pathogenicity test of fungal isolates on J. curcas
79
- Comparison of two inoculation techniques on the incidence of canker caused by Colletotrichum sp. on J. curcas accessions 81
- Leaf spot incidence on J.
curcas accessions at four weeks after inoculation 82
- Wilting incidence on J. curcas accession after four weeks of combined inoculation with four fungal pathogens 83
- Time lag between inoculation and anthracnose expression on selected
J. curcas accessions inoculated with Colletotrichum gloeosporioides 85
- Incidence (%) of leaf chlorosis (LC), leaf spot (LS) and leaf blight (LB) on J. curcas inoculated with Colletotrichum sp. 86
- Root rot incidence on J. curcas accessions inoculated with
F. oxysporum in the screenhouse 87
- Stem lesion caused by C. gloeosporioides on J.curcas shoots at four, eight and twelve weeks after inoculation 89
- Collar rot incidence (%) on J. curcas accessions inoculated with L. theobromae in the screenhouse
90
- Reaction of Ex- Misau accession to double pathogen inoculation of
C. gloeosporioides and Curvularia lunata at (12 WAI) 91
4. 15 Fresh plant weights of Jatropha accessions inoculated with C. gloeosporioides 93
- Disease incidence on J. curcas accessions at 3 and 6 months after field establishment 94
- Disease severity on J. curcas accessions for resistance to anthracnose under natural infection at 9 and 12 MAP 95
4. 18 Resistance evaluation of J.curcas accessions for anthracnose resistance at 4, 8 and 12 months after planting 97
- Incidence of leaf chlorosis, shot–hole and defoliation on J. curcas
accessions at 9 months after planting in the field 98
- Shoot dieback on J. curcas at 6, 9 and 12 MAP under natural field infection by C. gloeosporioides
99
- Disease severity on leaves of J. curcas plants infected by Oidum sp. at different seedling ages under natural infection
101
- Incidence of grey mildew caused by Oidum sp. on Jatropha accessions under three observation seasons 102
- Incidence and severity of root rots on J. curcas caused by Fusarium oxysporum and L. theobromae at three months after planting (MAP) 103
- Disease incidence and severity scoring of shoot dieback caused by C. gloeosporioides on J.curcas accessions under natural
field infection. 105
- Flower abortion incidence on J. curcas accessions caused by
Oidum jatrophae after six weeks of flower initiation 106
- Survival of Colletotrichum gloeosporioides on J.curcas seedlings at
4, 8, 12 and 16 weeks after planting (WAP) 107
4. 27 Anthracnose expression on five accessions of J.curcas seedlings
raised from 12 weeks old stored seeds 109
- Conidia shape and growth rate of C. gloeosporioides from infected plant parts of field-grown J. curcas; cultured on PDA at
room temperature 110
- Pearson Correlation between incidence and severity of disease symptoms measured in the field 112
- Leaf spot incidence and severity on J. curcas accessions in three locations (May- June, 2011) 113
- Leaf spot incidence (%) and severity on J. curcas accessions in
three locations (May- June, 2012) 114
- Leaf spot incidence and severity indices on Jatropha accessions in three locations during the dry season (Nov. – Dec. 2012) 115
- Influence of wet and dry seasons on the incidence of foliar blight on
J. curcas in wet and dry seasons of 2011 and 2012 117
- Severity scoring of leaf blight for different seasons in 2011 and 2012 118
LIST OF PLATES
PLATES PAGE
2.1 Jatropha curcas plant 9 (a) and fruits (b) 6
4.1a Initial stage of leaf spot showing (a) chlorotic spots; (b) necrosis
caused by C. gloeosporioides 49
- b Chlorotic spots (a) and Necrotic leaf spots (b) on J. curcas
caused by C. gloeosporioides 50
- Seedling blight showing brown necrotic patches (a) and gray burnt-like patches (b) on J. curcas in the field caused by
C. gloeosporioides 51
- Anthracnose disease on J.curcas leaves caused by (a)
C. gloeosporioides and (b) C. lunata 53
- Petiole infection on Ex- Mbatdiya accession in the field caused by
C. gloeosporioides 54
- Leaf chlorosis on Ex- Misau caused by C. gloeosporioides inoculation
(14 days after inoculation) 55
- Necrosis (a) and defoliation (b) on twig of J. curcas at 12months after planting caused by Colletotrichum sp.
57
- Length of necrotic portion (A) and the longitudinal section (B) on
J. curcas shoot due to Colletotrichum invasion 58
- Multiple twig dieback (a) and defoliation
- due to Colletotrichum invasion 59
- Lesion caused by C. gloeosporioides on J. curcas branch resulting in breakage
60
