TABLE OF CONTENTS

Title Page    –         –         –         –         –         –         –         –         –         i

Declaration  –         –         –         –         –         –         –         –         –         ii

Certification –         –         –         –         –         –         –         –         –         iii

Dedication   –         –         –         –         –         –         –         –         –         iv

Acknowledgements         –         –         –         –         –         –         –         v

Table of Contents   –         –         –         –         –         –         –         –         vi

CHAPTER ONE

1.0     Introduction – –         –         –         –         –         –         –         1

1.1     Background of the Study –         –         –         –         –         –         1

1.2     Scientific Classification   –         –         –         –         –         –         2

1.3     Uses of Citrus        –         –         –         –         –         –         –         3

CHAPTER TWO

2.0     DESCRIPTION OF CITRUS PLANT       –         –         –         5

2.1     Taxonomical Description of Citrus      –         –         –         –         5

2.2     Morphology of Citrus Plant       –         –         –         –         –         6

2.3     Origin and Distribution    –         –         –         –         –         –         7

2.4     Cultivation of Citrus        –         –         –         –         –         –         9

2.5     Health Benefits of Citrus –         –         –         –         –         –         10

2.6     Pest and Diseases of Citrus        –         –         –         –         –         10

CHAPTER THREE

3.0     FUNGAL DISEASE OF CITRUS    –         –         –         –         13

3.1     Phytophithoral Disease    –         –         –         –         –         –         13

3.1.1  Symptoms   –         –         –         –         –         –         –         –         14

3.1.2  Causal Agent         –         –         –         –         –         –         –         15

3.1.3  Control        –         –         –         –         –         –         –         –         15

3.2     Armillaria Root Rot         –         –         –         –         –         –         16

3.2.1  Symptoms   –         –         –         –         –         –         –         –         17

3.2.2  Causal Agent         –         –         –         –         –         –         –         17

3.2.3  Control        –         –         –         –         –         –         –         –         18

3.3     Pink Disease          –         –         –         –         –         –         –         18

3.3.1  Symptoms   –         –         –         –         –         –         –         –         19

3.2.2  Causal Agent         –         –         –         –         –         –         –         19

3.2.3  Control        –         –         –         –         –         –         –         –         19

3.4     Alternaria Brown Spot     –         –         –         –         –         –         20

3.5     Septoria Spot         –         –         –         –         –         –         –         21

3.5.1  Symptoms   –         –         –         –         –         –         –         –         21

3.5.2  Causal Agent         –         –         –         –         –         –         –         22

3.5.3  Control        –         –         –         –         –         –         –         –         22

3.6     Wood Rots   –         –         –         –         –         –         –         –         23

3.6.1  Symptoms   –         –         –         –         –         –         –         –         23

3.6.2  Causal Agent         –         –         –         –         –         –         –         24

3.6.3  Control        –         –         –         –         –         –         –         –         25

CHAPTER FOUR

4.0     SUMMARY AND CONCLUSION

4.1     Summary     –         –         –         –         –         –         –         –         26

4.2     Conclusion  –         –         –         –         –         –         –         –         27

             References

CHAPTER ONE

1.0     INTRODUCTION

Citrus fruits have been collected and used by man for centuries for medicinal herbal and agricultural purposes. Citrus fruits belong to the family of Rutaceae. Citrus fruits are one of the main fruit tree crops grown throughout the world (Okwu and Emenike, 2006). All citrus fruits share in common their sweet and sour flavor. They possess refreshing juice and are available almost all year round. Citrus species are small to medium-size shrubs or trees that are cultivated throughout the tropics and subtropics. They are native to part of India, China and Northern Australia. Brazil, China, the United State, Mexico, India and Spain are the world’s largest producers of oranges, China producers of oranges, China produces most of the world’s mandarins and India is the world’s largest producers of lemons and limes and the United State produce the most grapefruit (Wu et al., 2018).

1.1     Background of the Study

Citrus are among the ten most important crops in terms of total fruit yield worldwide, and it ranks first in International fruit trade in terms of value. More than seven million hectares are planted with citrus throughout the world. The term “Citrus” Indicates complex of species and hybrids of the genera citrus, Eremocitrus, Fortunella, Microcitrus and Poncitrus subfamily Aurantioideae (Family Rutaceae). It is assumed that all presently cultivated citrus species originate from three ancestral “true” species. Citrus medica (citron, Citrus reticuleta mandarin) and Citrus maxima (pummelo). Although citrus are native to East Asia, Citriculture has expanded in tropical, subtropical and the Mediterranean are the leading producers for the International fresh market.

The term “Fungal” disease referred to citrus pathologies which include tooth diseases caused by “true” fungi or fungi sensu strictor (eumycota) and those caused by oomycetes. In fact, although oomycetes are part of a distinct kingdom (Chromista or Stramenopiles), they are traditionally considered fungi sensu lato as they have in common with eumycota some ecological and morphological (e.g filamentous hyphae) features (Fuller et al., 2017).

1.2     Scientific Classification

Kingdom     –         Plantae

Division       –         Tracheophytes

Class            –         Rosids

Order           –         Sapindale

Family         –         Rutaceae

Genus          –         Citrus

Species        –         C. sinensis

1.3     Uses of Citrus

• Orange and grapefruit juices are popular breakfast beverages.
• Meyer lemons can be eaten out of hand with the fragrant skin they are both sweet and sour.
• Lemonade or limeade are also used for beverages prepared by diluting the juices of these fruits and adding sugar.
• Lemons and limes are also used to cook dishes or sliced and used as garnishes.
• Their juice is used as an ingredient in a variety of dishes.
• It can commonly be found in salad dressings and squeezed over cooked fish, meat or vegetables.
• A variety of flavours can be derived from different parts and treatments of citrus fruits.
• Lemon or lime is commonly used as a garnish for water, soft drinks or cocktails.
• Citrus juices, rinds or slices are used in variety of mixed drinks.
• The colourful outer skin of some citrus fruits, known as zest, is used as a flavouring in cooking the white inner portion of the peel, the pith, is usually avoided due to its bitterness.
• Typically, lemon or an orange can also be soaked in water in a coffee filter and drink (Khan et al., 2010).