ABSTRACT

The effect of five plant tissue extracts; Piper guinensis leaf and seed, Carica papaya leaf, root and seed: were evaluated in the laboratory to determine their effect on the germination of Cowpea (Vigna unguiculata (L.) waip) seeds and incidence of the seed borne fungi using two concentration of 50% and 30%. The cowpea seeds were soaked in each concentration of the cold aqueous extracts for 12 hours, removed and dried at room temperature for 8 hours. The cowpea seeds were then inoculated in Petri dishes for 7 days in an inoculation chamber. The experiment was a Completely Randomized Design (CRD) with 5 replications. The seed borne fungi isolated from the treated cowpea seeds were Fusarium sp., Colletotrichum spp., Curvularia sp., Mucor sp. And Aspergillus spp. The plant tissue extracts irrespective of their concentrations had significant (P< 0.05) effect on the germination of the treated seeds and on the incidence of the seed-borne mycoflora. The result of this study indicated that cowpea seeds dressed with aqueous solution of the root extract of Carica papaya (Pawpaw) irrespective of the concentration used gave the highest germination percentage of 100 whereas seeds treated with seed extract of Piper guinensis failed to germinate at both concentrations. This study further demonstrated that aqueous solution of the root extract of C. papaya and extract of P. guinensis seed significantly (P< 0.05) gave a better reduction of the incidence of the seed borne mycoflora of cowpea with incidence of 5.2% and 0% respectively at extract concentration of 50% whereas at extract concentration of 30% the incidence were 19.2% and 4.8% respectively. Though 50% aqueous extracts concentration generally gave higher reduction of the incidence of seed-borne mycoflora, in other words giving a better control of the seed borne fungi than the 30%, the germination of the treated cowpea seeds were better with 30% concentration of the aqueous plant tissue extracts. Based on the result of this study, the use of aqueous root extract of C. Papaya (Pawpaw) could be used as effective seed dressing phytochemical in 1PM programmes for the control of seed-borne fungi.

TABLE OF CONTENTS

CONTENTS PAGE

Title page ii

Certification iii

Dedication iv

Acknowledgement v

Table of contents vi

List of Tables vii

List of Figures viii

Abstract ix

CHAPTER ONE

1.0 Introduction

1.1 Objectives 4

CHAPTER TWO

2.0 Literature Review 5

2.1 Cowpea Diseases 5

2.1 .1 Use of Synthetic chemicals in plant Disease Control 7

2.1.2 Use of plant Extract in Plant Disease Control 10

2.2 Seed borne mycoflora and Seed Health 12

CHAPTER THREE

3.0 Materials and Methods 14

3.1 Location of Experimental Site 14

3.2 Source of Seeds and Plant Materials 14

3.3 Laboratory Experiment 14

3.3.1 Preparation of Plant Extracts 14

3.3.2 Preparation of Culture medium 15

3.3.3 Seed Treatment 16

3.4 Isolation and Identification of Seed borne Fungi 16

3.5 Statistical Analysis 17

CHAPTER FOUR

4.0 Results and Discussion 18

4.1 Results 18

4.2 Discussion , p 23

References 31

Appendices 37