ABSTRACT

The insect fauna of decaying Banana of Plantain pseudostems were surveyed in three neighbouring towns of Abia State of Nigeria between September 2002 and February 2003 and July to October 2003. The study involved dissections of cut decaying pseudostems, culturing of immature stages of insects to adulthood and use of improvised traps and trapping systems. Ten orders of insects were incriminated. The orders Coleoptera and Diptera were most prevalent with proportionate representations of 130.00 and 110.00 respectively in a pie chart. Most of the insects using the decaying banana/plantain pseudostems as a biotope spent their entire life on it except for dipteran species that use it for reproductive purposes. The Banana weevil, Cosmopolifes sordidus, Temnoschiofa sp. Amitermes evuncifer and Gonocephalum simplex were found to be of economic importance: Anopheles sp. is of medical importance. These species, with the others documented all play a role in aiding the decomposition process thus contributing to nutrient turnover. The abundances of the insects (except one) were not influenced by the amount of rainfall as they showed non- significance to the applied student t-test. Only the Rat-tail Maggot showed significance synchronizing its pupation period to the drier months of the year. The amount of rainfall also does not affect the population of Cosmopolites sordidus, which is the most important pest of banana/plantain in Africa.  (Musa spp.) are important food and cash crops with plantain serving as a major starchy staple in Africa (FAO, 1995). Total world plantain production is estimated at over 76 million tons a year of which export especiafly of the Cavendish banana) to the richer nations represents less than 11 million tons. The rest, of the said production, over 85% is made up of a wide range of banana and plantain varieties grown by peasant farmers or small holders and their families. Banana production alone is estimated

TABLE OF CONTEITS

Title page

Certification

Dedication iii

Acknowledgement ....... iv

Table of contents... . v-vi

List jftables vii

List of figures

Listof plates ix

Abstract X

Chapter One INTRODUCTION 1-3

1.1 INTRODUCTION 1-2

1.2 AIMSANDJUSTIFICATION 2-3

Chapter Two LITERATURE REVIEW 4-17

2.1 BANANAS AND PLANTAINS 4

2.1.1 Morphology 4-5

2.1 .2 Cultivation 5-6

2.1.3 Uses . 6-8

2.1 .4 Limitation to production: Insects pest 8- 1 1

2.1.5 Control of C. .sordidus 12-14

2.1.6 The banana/plantain pseudostems after harvest 14

2.2 INSECTS 15

2.2.1 The role of Insects in the decomposition process 15-17

Chapter Three MATERIALS AND METHODS 18-26

3.1 SITE DESCRIPTION 7-18

3.2 DATA COLLECTION 19

3.2.1 The Insect community on decaying banana/ plantain pseudostems....19-25

3.2.2 Determination of the relative abundance of C. .sordidus 25

3.2.3 Killing of insects 25

3.2.4 Insect identification 26

3.2.5 Data Analysis 26

Chapter Four Results & Discussion 27-51

4.1 INSECTS IN THE DECAYING BANANA I PLANTAIN PSEUDOSTEMS 27-40

4.1.1 Relative size of the insect community encountered . 30

4.1.2 Seasonal abundance of insect species 30-40

4.1 .3 Suitability of medium for decomposition and habitation 41

4.2 INCRIMINATED IMMATURE INSECTS CULTURED IN THE LABORATORY 41

4.3 INSECT CATCHES FROM NET TRAP 42

4.4 RELATIVE ABUNDANCE OF C. SORDIDUS .. 42-48

4.5 ASSESSMENT OF THE RELEVANCE OF ENCOUNTERED INSECT SPECIES 48-51

Chapter Five DISCUSSION - 524

Chapter Six CONCLUSION 55-56

REFERENCES 57-63

APPENDICES 64-67