TABLE OF CONTENTS
Title Page - - - - - - - - - - - i
Certification - - - - - - - - - - ii
Dedication - - - - - - - - - iii
Declaration - - - - - - - - - - - - - - - - - - - - - - .iv
Acknowledgement - - - - - - - - - v
Table of Contents - - - - - - - - - - .vii
List of Tables - - - - - - - - - - - x
List of Plates - - - - - - - - - - - .xi
List of Figures - - - - - - - - - - - - xii
List of Photomicrographs - - - - - - - - - xiv
Abstract - - - - - - - - - - xv
CHAPTER ONE
INTRODUCTION
1.1.1 Statement Of Problem - - - - - - - - .4
1.1.2 Research Objectives - - - - - - - - - .4
CHAPTER TWO
LITERATURE REVIEW
2.1 Classification - - - - - - - - .5
2.2 Origin and Distribution - - - - - - - .6
2.3 Botanical Description - - - - - - - - .9
2.4 Types of Papaya - - - - - - - - - - - .12
2.5 Growth habit and Soil - - - - - - - - - 14
2.6 Pollination - - - - - - - - - 15
2.7 Propagation - - - - - - - - - - 16
2.8 Harvesting - - - - - - - - - - 16
2.9 Nutritional value - - - - - - - - - - - 17
2.10 Economic Importance - - - - - - - - - 17
2.11 Industrial Importance - - - - - - - - .18
2.12 Chemical Compounds - - - - - - - - - 18
2.13 Toxicity and Allergy - - - - - - - - - 19
2.14 Health Benefits - - - - - - - - .20
2.15 Insect Pests and Nematodes - - - - - - - - .24
2.16 Diseases of Papaya - - - - - - - - - .28
CHAPTER THREE
MATERIALS AND METHODS
3.1 Culture Media - - - - - - - - 34
3.1.2 Reagents and Indicators - - - - - - - - .34
3.1.3 Laboratory Wares - - - - - - - - - .34
3.2 The Papaya Farm - - - - - - - - - - .34
3.2.1 Raising of Nursery - - - - - - .34
3.2.2 Tagging and maintenance of the nursery and farm - - - - - - - 35
3.2.3 Collection of samples - - - - - - - - - .35
3.2.4 Documentation of disease symptoms - - - - - - .35
3.2.5 Processing of samples - - - - - - - - - 36
3.2.6 Culture techniques - - - - - - .37
3.3 Sterilization of glassware - - - - - - - .38
3.3.1 Preparation of media - - - - - - - - - 38
3.3.2 Preparation of Papaya fruit agar - - - - - - - - 38
3.3.3 Isolation of microorganisms - - - - - - 39
3.3.4 Procedure for subculturing - - - - - - - - - .40
3.3.5 Preservation of isolates - - - - - - - - 40
3.3.6 Identification and characterization of isolated strains - - - - - .40
3.4 Biochemical tests - - - - - - - - - - .42
3.5 Identification of mould isolates - - - - - - - .45
CHAPTER FOUR
Results - - - - - - - - - - 47
CHAPTER FIVE
Discussion - - - - - - - - - - .89
Recommendation and Conclusion - - - - - - - - - 93
Contribution to Knowledge - - - - - - - - 97
References - - - - - - - - - - 98
Appendices - - - - - - - - - 107
LIST OF TABLES
Table 1: Shows production of papaya by region - - - - - - - - 8
Table 2: Showing fruit characteristics of papaya cultivars in major producing countries - - . - - .13
Table3: Chemical components of per 100g orange-fleshed papaya fruit - - - 23
Table 4: Shows sample types and distribution - - - - - - - 48
Table 5: Shows cultural and microscopic characteristics of fungi isolated from papaya
samples - - - - - - - - - - - 49
Table 6a: Shows cultural and microscopic characteristics of bacteria isolated from papaya
samples - - - - - - - - - - - 50
Table 6b: Shows the biochemical characteristics of bacteria isolated from the papaya
samples - - - - - - - - - - - 51
Table 7: Shows bacterial isolates from sooty rot and white fluffy rot of papaya samples - - - .52
Table 8: Shows fungal isolates from sooty rot and white fluffy rot of papaya samples - - - - .53
Table 9: Shows the bacterial isolates from a total of 33 samples - - - - 54
Table 10: Showing fungal isolates from a total of 33 samples - - - - 55
LIST OF PLATES
PAGES
Plate 1: Shows Aspergillus niger on Potato Dextrose Agar plates - - - - - .73
Plate 2: Shows Aspergillus flavus on Potato Dextrose Agar plates - - - - .74
Plate 3: Shows Staphylococcus spp on Nutrient Agar plate - - - - - 75
Plate 4: Shows Bacillus spp on Nutrient Agar plate - - - - - - - - 76
Plate 5: Shows Mucor spp on reisolation from papaya fruit sample of pathogenicity test - - .88
LIST OF FIGURES
Figure 1: Shows papaya major producing countries - - - - - .8
Figure 2: Shows the frequency of occurrence (%) of bacterial isolates from with soft rot of
papaya samples - - - - - - - - - - - 56
Figure 3: Shows the frequency of occurrence (%) of fungal isolates from papaya with soft rot of
papaya samples - - - - - - - - - - - 57
Figure 4: Shows the frequency of occurrence (%) of bacterial isolates from papaya with white
fluffy rot - - - - - - - - - - - .58
Figure 5: Shows the frequency of occurrence (%) of fungal isolates from papaya with white
fluffy rot - - - - - - - - - - - .59
Figure 6: Shows the frequency of occurrence (%) of bacterial isolates from papaya with sooty
rot - - - - - - - - - - - - .60
Figure 7: Showing the frequency of occurrence (%) of fungal isolates from papaya with sooty
rot - - - - - - - - - - - - .61
Figure 8: Shows the frequency of occurrence (%) of fungal isolates from papaya with soft rot,
sooty rot and white fluffy rot - - - - - - - - - .62
Figure 9: Shows the frequency of occurrence (%) of bacterial isolates from papaya with soft rot,
sooty rot and white fluffy rot - - - - - - - - - - .63
Figure 10: Showing frequency of occurrence of bacterial isolates from 33 samples - - - - - 64
Figure 11: Showing frequency of occurrence of fungal isolates from 33 samples - - .65
Figure 12: Showing the frequency of occurrence (%) of fungal species from papaya with rot
symptoms using papaya fruit agar - - - - - - - - - .66
Figure 13: Showing the frequency of occurrence (%) of bacteria species from papaya with rot
symptoms using papaya fruit agar - - - - - - - - - - 67
Figure 14: Showing ripe papaya sample with dark whitish coloration and sunken lesion - - - .68
Figure 15: Showing ripe papaya with soft rot symptoms - - - - - - 69
Figure 16a and 16b: Showing unripe papaya fruits showing sooty rot and white fluffy rot
respectively - - - - - - - - - - 70
Figure 17: Showing papaya stem with sooty rot and white fluffy rot - - - - 71
Figure 18: Showing papaya leaf sample with sooty rot and white fluffy rot - - - - .72
Figure 19: Showing the frequency of occurrence (%) of fungi species isolated from healthy
papaya fruits used for pathogenicity test - - - - - - - .86
Figure 20: Showing brown fluffy aerial growth from infected papaya fruit - - - - - - .87
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